I read about this before online somewhere and it happens to me almost every time I am on my way to the bus terminal, because they see a single farang with luggage. If the bus is full, I just hop on. If empty, they ask "where you go?"
They want 100 baht to go to the north bus station from Boyztown on 2nd Rd. I say "no thanks," because I usually can get to the Dolphin Roundabout for 10 baht then walk over to where another baht bus is going to the bus station for 10 baht. This last trip, the boyfriend and I explained this to the empty songthaew driver, so he accepted us for 10 baht each after insisting on 100 baht.
I think some things will never change, regardless of laws or army enforcement. A farang with luggage is an easy mark.
I was born with my heart on my sleeve, a fire in my soul, and a mouth I can't control.