My theory is that the "a few people" are kind of hardcore and may have multiple accounts. Say if a player has 3 accounts, then he/she has 3 times more chance to find a shiny than others. Also if they just pick up a mon and see if it's shiny, and release it without even catching if it's not, then they can further speed up to find a shiny one.
A problem with shiny RNG?
I played for a few hours today, caught dozens and dozens of nido females and luvdisks. Didn't find a shiny, outside of community days i only have a handful. Did a raid with 20 other people, no one there said they've found a shiny in this event.
For most players this is also true. However a select few seem to find shinys like every week and have multiple copies of most shinies. One person said they have six shiny karps. These are not necessarily the most active players either.
Do a select few players have enhanced shiny odds, or are they cheating?
Answers
It definitely contributes, Go Plus/Gotcha catches you mons you otherwise would never see. I got a shiny Growlithe recently thanks to my gotcha picking it up while I was riding a bus and I have at least a dozen other non-CD shinies all thanks to being able to catch mons even when I don't have Pogo on the foreground.
It's all "R"NG. I've caught shiny Poocheyna, Magikarp, 2 Swablu, 2 Makuhita and Roselia all outside of events. A guy I raid with has caught a shiny on the first catch after an event goes live on 4 different events - 3 of which were Raid Bosses (Ho-Oh, Lugia and after they announced Shiny Absol), one of which was a wild-caught shiny Pineco.
It's entirely, utterly, 100% "R"NG. Completely "R"NG. Nothing else.
Random is random is random. There's no rhyme or reason as to why some people have more luck than others, that's just how it is. I'm on the side that rarely sees new shinies as they're introduced - I never even saw shiny Moltres after nearly 30 raids. Someone I know seems to just stumble upon them. The only shinies I've caught outside of boosted chances like community days are a karp, three Aron, two Makuhita, a Swablu, and just yesterday a Luvdisc.
I'm gonna hijack this topic and say that for being a 24 hour event centered around Nidoran I saw very few of them or their evolutions compared to Luvdisc, Jigglypuff, and Wobbufett.
From my personal anecdotal observations, some players find some shiny pokemon more than other players, but then it will switch the next event and someone else will find more.
Random number generation can never be truly completely random. From my observations, I'd guess they might be utilizing some seed values that include some kind of player ID number thus causing some players to occasionally have better chance than others.
Generally speaking it goes hand in hand with activity and how much you grind. For example I got 7 event shinies from the Fighting event but I played like a madman and hit the catch limit (then 3500 mon per week) during that time.
Now if you have people who aren't that active but still have a lot of shinies, they could be lucky, or they could be multiaccounting. Or maybe you don't have the right picture about how active they actually are. And then there's the question of how good the RNG is and I must say shinies have made me very suspicious because I know of way too many instances of two people having the same spawn be shiny (should be stupidly unlikely at 1/202500 odds) and some people who consistently score above the norm with their shiny luck.
PS. There's absolutely nothing extraordinary about six shiny karps. I have seven shiny karps out of 2947 caught. It's the oldest shiny and anyone with the golden karp medal is likely to have several sparkly goldfish.
I don’t think it’s cheating or that they’re selectively more lucky. It’s just statistics. The odds are about 1/450 for non event or raid shinies. That doesn’t mean if you catch 450 Pokémon you’re guaranteed a shiny, and it also doesn’t mean you need to catch 450 to find a shiny. The first Swablu I ever clicked on was shiny, but I’ve caught hundreds of other Pokémon without seeing their shiny variants.
Every time you click on a Pokémon you have the same odds, so it stands to reason that people who play often and click a lot of Pokémon will have higher odds of finding a shiny. I know people who hunt them for hours at a time, often traveling to nests of certain Pokémon.
I have great luck overall with shinies when I am not actively looking for them. It took me more than half a year to get shwablu, but I get most shinies within the first 10 encounters every time a new one is released. However, I know this is just me finding patterns where there is just happenstance.
People forget "luck" is not a real/life value that can be measured like in videogames. "Luck" is nothing else but humans' tendency to seek observable coincidences in multiple occurrences of the same or similar events. There are millions of GO players worldwide. EVERYTHING that could happen will happen, no matter what. No matter how improbable, it is not impossible for a whole community to not report a single shiny encounter during a shiny release. it is also possible that they all find one. It is possible for a player to have every single shiny released and there is someone out there without a single shiny.
What I am saying is that you cannot concoct any kind of theory out of your own personal observations about any event when it revolves around purely informatic randomness. Not even if the data points are as big as a whole community of 50+ or even 100+ players. That is a bad practice and there's probably a technical fallacy named after such drawings of biased conclusions.
I also wonder whether the randomness is skewed somehow by trainer ID, etc. Just to give you a couple examples, I've done 25 mewtwo raids in the past few weeks. I've never seen a mewtwo with IVs over 84% based on their cp. Someone I know has done almost 50 mewtwo raids in the same time period. Unlike me, he's only encountered five with IVs UNDER 90%. Yet, in a strange twist, he's only caught two (out of about 50) with a 15 attack stat.
Yes, I know this is all entirely possible when dealing with small sample sizes, yet the combination of the three situations above occurring together is likely incredibly slim.
Catching More Pokemon is the best way to increase your odds of finding a shiny; those people with Go Plus or a Gotcha Device will be able to catch more pokemon, thus increasing there odds. I would recommend maybe going to a nest that has a Pokemon with a shiny version (i.e Krabby Nest) that's probably where you have the greatest chance