I think you might be right, HOWEVER, if someone is deliberately trying to screw the immigration system, they should have the extra precaution handy. Thai immigration doesn’t do favors for people. Their function is to stop people from attempting to live here without proper documentation, trying to pass as tourists. A return ticket to my home country is more credible than a cheap ticket out on a low cost airline or a completely bogus airline ticket.
Fortunately it doesn’t affect me directly because I have a non -o and am about to do extension #4. But I get frustrated at those who deliberately test the system and plead ignorance or complain about the immigration laws here. Many foreigners apparently feel as though they should be entitled to stay in Thailand unconditionally.
There are things to complain about Thailand, but this not one of them. It is those who abuse the system by trying to outsmart it that causes problems for everyone else.