Strange that you say when an account is flagged by your provider betby, that you request KYC from the account holder to proceed. You never even got that far with my case or even asked!
If you run a business, do you ask for advanced documents for your investigation on one customer account if you did not smell anything suspicious?
When you smell it, you will do more deep investigation and more requirements will be sent to a user. Additional requirements are not to beat that user down but to make sure the investigation is correct and original doubt can be verified accurately that whether it is correct or invalid.
If it is proven as invalid, both sides will feel happy. If it is proven as valid, only the user will feel bad.
I know what OP is speaking of. If he has a phone such as T-mobile that gives unlimited international roaming, it would still show as US ip address on his phone even tho he is connected to network in germany. It is a strange thing that I have read about.
Residency can mean submitting proof of address in Germany, the US ID wouldn't matter as they don't care about citizenship rather where you actually live and are located.
With that suspicious IP address, Rollbit team can find more in that user login details.