Ive always stayed at the dynasty grande inn and liked the place. Ive taken 2 lbs before they never said a thing, its just one time i got pulled up on it and they were telling me that room is for a total 2 people and anymore is 500 baht.
It might be hit and miss but the decision im leading towards is
The difference between majestic grande and the DIG is about 700 baht and read some good reviews on the majestic.
If Majestic dont have any guest fee for extra person, well i made aswell stay there true.
Im sure this might be the case for another places or even stay somewhere lower end and bar fine a 3rd lbs 5555555555 (struggle with 2 let alone 3)
Ive had this issue at a place in patong once before aswell and did the same thing.