Jumping to a whole new thread:
Depends on which festival you're at as far as how "historical" faires can be. The one here - MnRF is terrible. There is no attempt whatsoever at any accuracy for any one. That's why I do living history (www.clanntartan.org.) My character is researched, I've written and published 2 papers so far on my character and profession, and I've done some extensive research on my time and place. I can give you chapter and verse on Scotland in 1630, political, religious, weather, customs, and about anything else you want to know. This has nothing to do with festivals. Sometimes, we are payed performers *at* RenFaires, but we are not cast. We are living history.
Some faires do moniter accuracy for the performers - not the mundanes who come in dressed in any old way. Again, as someone pointed out, this is a cross section of the country. I believe I'm the only regular poster from the northern Midwest (AKA Minnesnowta,) and thisngs are very different even a short distance away. I've heard wonderful things about Bristol and KCRF, and not from other Wenches - mostly from crafters.
What you see at one fiare will be very different from another faire - even faires in the same state. It all depends on who runs them.