Have you ever been asked before? I've never been asked in 30 years of regular air travel. I suppose that if the camera or lens was in the manufacturers box then that might be a different matter, however I don't tend to travel with them packed in their boxes!My big concern is the vat issue and bringing it back into the country when returning from a vacation. I have never seen any reports regarding poor service though.
I spoke to my local Canon authorised repair centre about Panamoz before I bought a 5DIV, they said that they deal with Panamoz every now and again and have had no problems.