How many back-to-back 15 day visa exempt stamps are acceptable nowadays, or no limit ?

There is no official limit for visa exempt entries into Thailand..

However they have said on several occasions that after three they may be asking questions to try and weed out those that may be working. We have also had reports of such questions being asked but not of any refusals.

However they have said on several occasions that after three they may be asking questions to try and weed out those that may be working. We have also had reports of such questions being asked but not of any refusals.

Do you know at which border entrances these questions were being asked ?

North borders but not sure if Burma or Laos (or both).

North borders but not sure if Burma or Laos (or both).

I see.