Used tires -- Watch out, re-grooves!

I had seen this video for the first time around two months ago when it made the front page of a very popular Finnish paper, Ilta-Sanomat.
I thought nothing of it at first just some local Finn having fun and showing off, maybe after a few drinks.
Now, this video has shown up as well on the Road&Track website in this article: http://www.roadandtrack.com/car-culture/buying-maintenance/news/a25247/watch-how-scammers-make-dangerously-worn-tires-look-new/

This is no laughing matter, this is extremely dangerous. These people do not care if somebody gets hurt or killed, take a look at this you tube video below.

Under the rubber tread that we see are steel belts which reinforce the tire, at the same time these belts need to be protected from denting by a certain thickness of rubber. Once this rubber is thinned out the steel belt protection is compromised. Steel belts are used to reinforce the area under the tread. These belts provide puncture resistance and help the tire stay flat so that it makes the best contact with the road.
More on how tires are made and work on howstuffworks.com link: http://auto.howstuffworks.com/tire1.htm
 

What you should look for in used tires are these wear bars on the above photo. According to most mechanics once this these wear bars are even with the tread the tire's useful life is over.
Be very vigilant when purchasing used tires through private sellers, always look for these wear bars to give you an indication of the tires remaining life. These wear bars would not be present at all if the process used in the video was performed on them.