I'm going to have to agree with Blukikatina on this one, the whole "let's ban everything that looks even remotely threatening" idea is pretty dumb. If you're banning pokemon on the merits of being 'overpowered', round up stuff like Gyarados and Tyranitar which are much bigger threats in DP than such legendary pokemon as Raikou, Suicine, those weaklings Entei, Moltres, Articuno, etc.
And even if he did break a rule, albeit an arbitrary one with little place in any competitive environment, he did so unknowingly and should not be faulted. Give him a second chance, he is the better battler and the results will almost certainly be the same.
You might make the argument that Scyther himself would bring in stuff like Jirachi, Zapdos, etc. had this rule not been in place, but it really isn't valid because many teams function well without Cresselia and legendary co.
Anyways, are you almost ready Trey? I'm waiting on wifi. Check in to chat.