I've been wondering a lot about this one myself. It's not so much the pick pockets I'd be worried about as what can happen at the airport security points. They make you put everything in those bins and then you can't even stick with them in case something goes wrong!
So potentially while you are being scanned your camera is out of sight. I almost lost my Fuji that way a few years back that way, but if you ask them to physically hand you your gear they don't like to do it. You can't keep it in the case sometimes either. Used to be able to, for cameras if not laptops, but last time I went they had me upend it all into a bin.
My camera was completely at risk and I came through just in time to catch some guy clearly looking it over to see if anyone was looking and it was worth the grab. I saw it and quickly took it up, but I think if I had been only 5 seconds later my gear would likely have been gone.
I just don't know if I'd take something like a DSLR over even though it would not be nearly as nice to use something else. Not unless I was completely insured in some way to cover the loss. I couldn't afford to save up like mad for both then take the trip of a lifetime only to lose my best camera. Artistically I'd hate not to take it, I mean it's EUROPE, big sigh, but then again I'd hate to lose it too.