As long as you keep a 2,000 Baht balance you will be fine as many have already said.
The only possible issue is that some Thai banks will automatically lock the account as being "dormant" if there are no deposits or withdrawals on the account for a consecutive 12 month period.
If an account goes into dormant status then it might require a visit to the bank in person to get the account unlocked before you can use the account again or get access to your money.
Best to do any small transaction in the account at least once every 6 months and you'll avoid any of these possible problems.