Not sure if this is the right place to post, but I just came back from an after work event
at City Hall, London, UK.
We had to go through airport style security to enter --- so I got to see my messenger bag under x-ray inspection!
These days I usually EDC a PS4 Squirt and a TaoTool package opener. Both have small blades. I decided to leave these at home because I knew we might be searched before entry, and I was right to do so. There was a sign that said penknives or fixed blades were not allowed, nor were pointed tweezers and other mildly pointed items, and even.... helium balloons!
That last one stumped me --- how dangerous are helium balloons?