I think it's crazy for anyone to wear a Santa suit at Christmastime in Australia. Today is predicted to be 34C (93F) and tomorrow will be hotter - and Sydney's one of the milder places in the country in high summer.
The equivalent would be having Santa running around in budgie smugglers in the middle of a snowy northern hemisphere winter.
Once -- just once -- I played a gig wearing a Santa hat I'd picked up at a drug store on the way to the gig. I don't remember when or what the gig was, but I do remember the crazy Chinese synthetic fibers and probably radioactive dye mixing with my sweat and making me break out in a monumental case of hives and prickly heat all over my head, face, and neck. So I don't gig at Christmas anymore.
I have played part of a gig wearing a Santa hat. I didn't break out like Al, but it was unbelievably hot and I ditched it. For Halloween I have gigged as a caveman, a woman, a pirate, and a hobo. Only the hobo looked realistic.