The only time we've ever had an issue with camp fires was our first year at Fforest Fields who provide firepits and good quality logs. However, our neighbours decided they would rip down every reachable branch from the trees and create their own fire. The following morning I could see the sky through my porch which we had to seal with good old tenacious tape.
There is a place for campfires on site, we love to sit round our firepit, but unfortately there are also idiots who don't listen to advice and spoil it for others.
If you are worried I suggest you avoid sites that do allow campfires, although be aware that some sites don't always uphold their rules. We stayed on one site who didn't allow campfires, and had signs on the site, yet one family in a caravan not far from us lit a huge fire in their BBQ every night and nothing was said.
------------- May/June - Spring Valley
Aug/Sept - Leekworth