Thumb Inside Pistol Grip Legal?

Hoping that some of you with a greater understanding of grip rules than myself can answer this. I was under the impression that sticking your thumb inside the sleeve of your opponent, then wrapping a pistol grip around it, was not only very dangerous to your thumb, but illegal under sport BJJ rules. However, I've been watching some competition videos of Alexandre Pulga, and he appears (on the grainy youtube clips) to use this grip consistently and with great success. The refs never warn him and his opponents never complain.

Is this grip actually legal? Is it not as dangerous as I've been told? Is it much more effective than a normal pistol grip? Am I hallucinating, and he isn't using this grip at all? Thanks in advance!

The rules say you are penalised for:

"When the athlete inserts his fingers inside the sleeves or pants, or with both his hands on his opponent's belt."

Seems pretty clear cut, unless you can argue that thumbs are not fingers :)

I can't see the vids at work, but the rules seem pretty clear.

Ttt

thumb can go inside sleeve can't it? not pant leg but arm sleeve i thought.

no fingers inside....

the pants will only get called by the ref if he feels you have been there too long. if you put fingers in the pants and then sweep, they wont say a thing.

fingers in the jacket are a no no. that will get warned each time.

you dont need the thumb inside to get a pistol grip on the sleeve. you can stick the thumb in for s second to get the gri and then get it out once you are set ( before anyone notices) heh

Let them leave their fingers in there, wrap your gi around, circular motions with your hand, and make it tight on their fingers. After all is said and done, pull your arm away with all your might. If they get mad or if something breaks its their own fault. Two wrongs makes the cheater hurt. You technically aren't cheating.

thanks guys, ttt one more time for any refs or people with personal experience with this. Although I played around with it for a few moments last night, and my thumb did not feel safe...