Well I am worried because I already got kicked off of Gemini. But maybe they have more stringent standards? I will be dealing with large amounts, what kind of extra verification would they require?
Probably the source of funds. Where did the crypto come from? where did the fiat come from? They can however and probably will drag this for a very long time (and we have seen many cases where this happens in the past).
So again, if you're not willing to provide any of this stuff to them or you just don't want to deal with the headache and end up making multiple Reddit posts about this matter on /r/CryptoCurrency, /r/Kraken or /r/Bitcoin, tagging them on Twitter, and opening a scam accusation in bitcointalk etc. You should probably just stay away.