It is summer in the Northern hemisphere of planet earth and this means that we have music festivals. Traditionally at the festival area you have two checkpoints, one for the entrance bracelet and one to inspect the backpacks for drinks.
The funny part is that people smuggle in drinks because it is kind of a challenge. My theory was if the man that would check my backpack would find something he would be happy and stop looking through the rest of my backpack.
I packed my bag with 2 glass bottles of Belgian beer, put them inside my sweater and put all the rest of my bicycle gear in my backpack. The thing I had planted for the man to discover was a deodorant spray. When you just pad the backpack it feels kind of like a can of coke when you are unexperienced.
I stood in the queue and when it was my turn, I presented the backpack and opened it cooperatively. I showed that I had my gear like my helmet and everything what you need to bike in a city, and the guy started padding the backpack. He found the deodorant and he asked me immediately what it was. Instead of answering him I opened up the backpack showed him the spray and he was happy with the answer.
I gave him a frame of "the guy on his bike" so the big backpack made sense.
As expected the man had a flow in his mind:
1. look into the bag, when no bottle visible goto 2 otherwise confiscate bottle
2. pad the bag, when nothing let through, when something ask question
The security problem was clearly in this last part, he knew he had to confront me with the fact that he had found something but when he was given an explanation that was different from "shit, bottle found". He was happy because he had the positive feeling he had done his job.
For your information, my friends and I still buy our beers at the festivals, but as I said before it is kind of a challenge to see if you can beat the system.