I wasn't banned from coinbase but I had my instant max amount reduced to the lowest amount and had to wait 2-3 day's for a ticket and email correspondence for them to tell me that it was a mistake when migrating users (And as far as I know it had been like this for a week or two)? I wasn't doing anything illegal or account flagged and if my actual bank was making casual errors about my account (i.e. suddenly my ATM withdrawal limit is reduced to $100 per week) I'd be incredibly suspect about their practices/intentions.
