Of course it has to be up the the individual and the primacy of their individual conscience.

But when you think of it there are plenty of other things that could potentially distract at a Mass - ladies hats, priests' and bishops' vestments, organists playing wrong notes...

And once you are in your pew you are normally there for most of the service, except when coming forward to make your communion so I would think that any distraction caused would be minimal.

I'm no longer a practicing catholic but when I was I saw people attending in all kind of different gear here in Wales and in Scotland catholics are just as likely to be kilted as their prebyterian and episcopalian neighbours on a Sunday.

Maybe it's more of a "novelty value" problem in the US?