I was in a K-Bank branch on Friday, not for forex, but it was otherwise operating quite normally. All the exchange booths around Bangkok seems to be functioning as normal; certainly Superrich is ( although I was the only customer in the head office late last week)
I think these concerns stem from the report that the virus can stay ‘alive’ on bank notes for a period of days; possibly, give higher levels of xenophobia than usual in Thailand at the moment, there could be some suspicion of “dirty” foreign money.
Perhaps people will start ironing their cash ( although I’m not sure the polymer notes wouldn’t melt...).