why would they have trouble? It's their money. Bangkok Bank will freeze your money for 4 months if it hasn't been in your account for 4 months, but they don't do that in future years if you keep your account balance at that level
Money in your Thai bank account is not CASH. You have to understand, if they ask you this question, it's because they already want to deny you entry. They're not going to accept things that aren't in the law, which states cash.