The two that I saw were indoors and may have been employees of the mall - the store most certainly knew they were there by the attention they drew, which is probably why they allowed or encouraged it. Both had substantial props like the table and chair the bronze man above used - and their make-up was far more meticulously done than the examples you'd see in most larger cities in the USA, perhaps worldwide - you tell me.
Bronze Man had the motor control to seem as though he actually was solid metal for an extended period of time, but 20 baht in the skillet on the table would put him into fluid but mechanical movement; folding the note, putting it into the cup, taking a sip from the cup, that sort of thing. Depending on the crowd and the amount donated he varied his "performance" between 30 seconds and a minute or more before once again coming to rest, motionless.
[To answer the probable question in advance: I was out with a handful of the students I sponsor, so I've diffused and altered a face in the interest of privacy. I only had one good photo of the "statue" guys.]