@Andrea ************
Yes your correct, if they deem your entry into Thailand out of category and you can’t provide them with the information they request or require they’ll cancel the DTV.
If the DTV visa is cancelled, you can still enter Thailand on a visa exemption (or a Visa on Arrival if your nationality qualifies). And they’ll stamp your passport and allow entry accordingly.
However, immigration officers will closely scrutinize your travel history and plans to ensure you are not abusing the system.