Here we go
Hooligans have experience (remember the bit about young officers selected with leadership in mind etc etc), most of the guys going for selection have a number of years experience in which their leadership skills have been developed. Rarely do you get an NCO going straight for selection straight after basic trg.
And HS, we all know that any system is not fool proof and there will always be those that slip through the net (just like there are some real knobs of the commissioned types, there are some equal to$$ers in the NCO world) - I would hope that in all cases natural selection weeds them out!!