Peeve #4- This one applies only to Scottish/Irish/ Celtic festivals. Ren Fest goers showing up in Ren fest costumes, like it's the two types of festivals are the same thing. It's annoying. I show up in my Ren Fest clothing because I'm with a living history group called the Renaissance Scots and it's appropriate for me, as it's part of our represented time period. But if you're a festival goer... it's just plain silly.
It's one of my peeves too, but a thought occurred to me today as I was driving home. How many of us have worn our kilts to a Renaissance Faire? I wonder if these people see that and think the two worlds go together. In other words, if we wear kilts to the Ren Faire, are we not somehow inadvertently inviting them to wear their costumes to a Scottish event? They may think so. After all, a kilt is hardly a Renaissance costume and really doesn't fit in with the genre (well, maybe the earliest belted plaids might just squeeze in the later years of the Renaissance, but you get my point).

I dunno, it's just something to consider.