Anonymous ******************
@Natasha ************
no, but it's true that doing the 90-day report isn't particularly difficult, it's free and just requires a short visit to immigration office. If you don't want to take a chance just go do it...
But not doing it will only result in a fine (no ban) IF and when you require immigration services after your initial 90 days.
If you leave and come back you can start the process again from a new entry. If you already plan to leave the country soon, and if your stay in Thailand is very temporary then you shouldn't worry about it too much it won't cause you a big problem like getting banned or deported... However if you plan to live in Thailand long term without leaving the country and you think you will require immigration services later on then it's important to do the 90-day reports in order to avoid a 2,000 baht fine in the future.
Basically once you've been in the country for more than 90 days and haven't done a 90-day report you cannot access any immigration services at the immigration office without paying the fine.
Also the fines don't stack up, if you miss multiple 90-day reports the fine will still be 2,000 baht whenever you seek services at the immigration office