Really? I'm not trying to be argumentative here - and I'll allow for the possibility that sometimes rules can be broken to positive effect (although within semi-formal wear I can't say I've ever seen it) - but you're suggesting something different, which is that breaking some rules has value for its own sake. Which I really don't understand. Particularly in a setting that is now so rare that few people know the rules anyway. In that case, don't you just want to look as good as possible? And can you deny that the rules in this case pretty much ensure that?