This guy was stopped and forced to remove his shirt at Heathrow airport in London.
From the blog::
No t-shirt, no flight
Going out to Dusseldorf for work.
Flying British Airways, leaving from terminal 5.
Go through security, get pulled to the side. I'm wearing a French Connection Transformers t-shirt. Bloke starts joking with me is that Megatron. Then he explains that since Megatron is holding a gun, I'm not allowed to fly. WTF? It's a 40 foot tall cartoon robot with a gun as an arm. There is no way this shirt is offensive in any way, and what I'm going to use the shirt to pretend I have a gun?
Now here's the stupid part. I was only taking carry on luggage, so my clothes were in my bag, so I said I'd get changed. So I stripped off at security and changed t-shirts, putting the "offensive" t-shirt in my bag. Now I haven't been a dick so far, I've done what they've said. No point in arguing with the drones.
The supervisor comes over and is now a dick to me, telling me if I put the shirt on I'll be arrested. I then told him that I wasn't going to waste time arguing with him and he wasn't worth the effort and didn't have any power to change anything anyway. With hindsight I should have said, yeah arrest me, great publicity for you guys to arrest a bloke wearing a transformers t-shirt.