Niantic, how do we know which gyms we have raided at before?

I was just thinking this. How terrible would it be to arrive at the gym to find out you can't join.

It sounds like the exclusive raid pass will let you know where the raid is going to be. You shouldn't have to worry about keeping track of which gyms you've raided unless you want to know which you haven't raided to you can increase your invite chances.

Don't worry too much about it. This is a simple trick to make people spend money on magikarp raids. Do you seriously think that Niantic will exclude people from Mewto raids if that can increase their revenues? I'll keep repeating this to anyone who worries too much about it. Niantic scumbag moneymakers