Are you in a hotel or residence? They seem to be clamping down on this TM 30 thing in some places....probably mostly in Pattaya though.....catching a lot of people out recently if Landlords don't register you.
As far as I know once you get to 90 days of overstay, you have to be outside of the country for 1 year, it can't be overturned (well perhaps with another bribe), that is why they continue to pay...??
You never get asked on arrival to Thailand. The most likely is to be asked by the airline if you do not have a visa or if you have a 1 time visa, ie 60 day. If you have a visa that is multiple entry it is unlikely that you will be asked as you are able to leave at any time and return at any time......so why would you book a specific ticket.