I seriously do not think that all camping festival are equally bad security wise. The smaller ones have always been fine IME.
At Glastonbury, tent theft has declined massively, to the extent (IMO) that if aylee's friend had a tent theft last year or next year, it would be REALLY worthy of comment as something well out of the ordinary. At WOMAD, which is near a town that has its fair share of scrotes hanging around the town centre, Stig had her rucksack taken from inside the tent last year while she was asleep inside!! but it was recovered later, because almost all of the gang responsible (locals, not 'tentrobbers on tour'

) were arrested. Plus the WOMAD organisers have promised an extensive upgrade to campsite security for 2006. At Beautiful Days last year, beer tent rumours of a gang of thieves proved entirely unfounded -- perhaps they were scared off when the perimeter security increased their patrols, and we never saw witnessed or even heard about any trouble.
I've been going to festivals for well over 20 years, including the scary Glasto years of 1994-2000, and have only had a bag taken once (in 1994 -- in the much worse year of 2000 I knew where to camp away from likely trouble!). I'm quite festie-smart though, the limited valuables I take, I always carry around with me.
The worst for (in)security sound as if they're V and Leeds.