They can't stop me.
I'll just have to go for vodka in a mineral water bottle.
Heh, reminds me of the time I snuck alcohol into the O2 wireless festival, I had got free tickets to go to two of the 3 days, first day with a couple of mates, 2nd day just me. It's not an alcohol free festival, but they want to force you into paying their ridiculous prices, for a limited selection. I decided I was going to break the rules.
First day, I got a bottle of vodka, got a loaf of sliced bread, took off the end slice, and hollowed out the middle, inserted the bottle, and put the end slice back on. When I was being searched, they asked "why have you got a loaf of bread" I simply replied "I am meeting my mate inside, he has some peanut butter". I held onto it, so they didn't notice the weight. This technique is called the "lucky loaf"
Anyway, whilst there we bumped into the event coordinator, a very friendly woman, around 40. Me and my mates flirted with her for a bit, and got into the VIP area instantly (it was free, but you were supposed to queue up for a wristband), in there, we got chatting to a bunch of the O2 staff, and they agreed to pick us 'randomly' to go up on the O2 bus (and get free drinks and a good position to see the bands).
The next day, I turned up a bit early, since I had nothing else to do, I had a load of alcohol in bags, but was planning to befriend some randoms, and just get wasted before I went in. However, I saw a bunch of guys with big cameras walking in early, they had black wristbands on (I still had my navy blue VIP wristband on) so I followed them, assuming I would be asked for my ticket. No one asked me anything, I just walked straight in the press entrance, and hadn't even used up my ticket! I phoned another friend (who loved massive attack but had never had the chance to see them) and she met me at the gate. I gave her my ticket, she got in for free too!
I then went to the VIP area, with my big bags full of alcohol, and the event coordinater saw me, so came over to say hi, and offered to keep my booze in their fridge, and let me come and get it as I pleased.
I love festivals so hard.