Is it possible to enter Thailand multiple times on a visa exempt basis before applying for a visa?

You have unlimited visa exempts by air, and 2 times a calendar year by land. "Unlimited" is defined by the immigration official on duty.

If the reject you, you'll go to the immigration detention center until your flight. If they know you have a flight out the next day, I can't imagine they'll put you in the immigration detention center.

Having a visa also does not give you the right to enter Thailand. If you are only here for one day, I believe you're ok. Keep the three proofs of ticket out of Thailand, the hotel booking, and the 20K THB on you and you'll be fine.

i think you are fine,. There is no limit on how many Visa Exempt you can use while flying into Thailand. You may be asked to show 20.000 Thb or equivalent currency in cash, proof of accommodation and proof of onward travel. As you have the ticket to Europe the same or next day, it should be no problem.

I saw this "information" also. This is Thailand. There are rules and there are "rules". Every "rule" is open to the interpretation of the immigration officer. The more times you come to thailand in a short period of time, the shakier the ground becomes.

cash. Ticket out. Accommodation booking. Those 3 things all help.