It only fails when you do not meet the requirements - If this dude had 20,000 baht,a hotel booking, and a plane ticket out of thailand, he would have been let in. There is no limit on entries nor visas.
To be honest, I do a similar thing - based out of BKK but don't technically live here.For the record, I certainly don't work in thailand. If you are going to bounce in and out with visas, trips home and border hops, you need to make sure that you have EVERYTHING. I carry 700$ in USD whenever I enter Thailand, I also have plane ticket out and hotel booking. You would have been fine if you had 20k cash in baht.