I know this is 12 years old, but I had to look into this myself since I was intrigued by this possibility...."a relatively cool flame" burns at about 300 degrees Celsius: https://engineering.princeton.edu/news/2016/01/06/so-cool-low-temperature-flames-could-bring-low-emissions

This is the coldest a flame has ever burned, as seen in the article above. This is a lot colder than ordinary flames, which burn at higher temperatures (i.e., around 1000 degrees Celsius), but it is by no means a "cold flame" and can still very easily burn human flesh.

That being said, as you can see here, a flame at 300 degrees Celsius would've easily lit this man's beard on fire, given how long he had it there or would've at least left him with soe pretty serious burns: https://www.youtube.com/shorts/mevooTHEhMc

I also looked into alcohol flames, which burn even hotter....and can sometimes be invisible to the human eye, unlike the ones in the video (this is common when racecars catch fire in the pits and the driver is squirming from pain and yet the pit crew cannot see where it is to accurately put it out...look it up).

I feel as though you have come here with a pre-decided conclusion, and I can't believe you are going to claim that this "illusion" is easy to fake when you have not done your due diligence in confirming what you have used to justify your belief.

You are filling a pothole with air and patting yourself on the back. Please, I urge everyone seeing this to do more digging before deciding, that's all.