Sid.
The move that Sawtanang is talking about isn't a throw as such. It's off balancing your opponent over your standing leg.
This move is used also in Judo, it's called Sasi tsuri komi ashi.
It isn't a "throw" in judo either, it is a move in which the leg is used as a "prop" with which to turn the opponent. Sumo uses it as well.

Sandy.
I didn't know that "throws" were legal in the All-Styles fights of the BTBC?
I never recalled ever seeing/experiencing anything different about the rules between the BTBC and the BTBC All-Styles championships.
I'm aware that fighters from different styles had a go, but it was more of an 'open Thai boxing championship' than a different rule set.

The All-Styles titles were brought about to bring into the BTBC bossom the growing number of clubs that weren't members, like Sale West and Trojans (the BTBC was basically Sitnarong) and (most people outside the BTBC believed) to protect the BTBC championships for the 'in-house' fighters against some strong contenders.

It didn't matter anyway, nearly everyone in the early days used illegal throws. And the corners were cheering and banging the ring aprons in approval.

Sid.
Are you sure BTBC scores kicks to the groin. Is this Pre or Post Sken?
Do you mean push kick to the groin?
I wouldn't think Tony Moore is the type of guy to invent his own version of the rules for Thai Boxing.

Mark.
Here in the uk i can't remember how many times i've seen the ref gesture some kind of warning about throws (Mt legal) not being allowed. Why? I can't tell you? Sometimes i cringe at the various interpritations being put on the rules by officials.
Personally, when you see fighers who don't know the rules of the sport they are meant to be fighting, being referee'd by ref's who don't know the rules of the sport they are reffing, i sometimes think they deserve each other. Leave them alone and let them get on with it :-)

Colin.
Independance is something i've always said was required. Even if all the organisations agreed to go with that, then that would be a start. But then they make money from giving out qualifications so that ain't going to happen for a while.

What is a sweep?
Turning/off balancing your opponent over your leg is fine. If you assist the ‘throw’ by moving the leg in a motion that isn’t a kick (eg. drive the leg through) then it’s probably going to be a sweep.
Somewhere there is a line that defines how much drive of the leg makes something a kick. Danny Bille mastered the limits of legality with his often used technique.