Just a bit of advice here.

Always bet on the fat kid.

All a matter of simple physics really. The object is grapple, or pinning your opponent down by the shoulder blades for a length of time. A fat kid has a lower centre of gravity than a thin kid and can use his weight to advantage, and once down stands more chance of pinning for the three seconds or whatever it is...

On a serious note, this does appall me, but at the same time, both my lads did karate and judo from a young age. I suppose I didn't let them in a cage in front of a load of drunken idiots screaming at them and waving wagers.

Silly old fashioned me.

Regarding children on the premises after a certain time, that applies to punters. Such rules (unless prescribed in law or licence requirement) don't apply to the "entertainment."