If you carry them in your hand luggage, I don't think you will have any problems. I even shot Ilford Delta 3200, pushed at 12800, took it back home undeveloped, and didn't notice anything wrong with it.

BTW, can anybody indicate some good photographic shops in southern Spain (Seville, Malaga etc) , offering a good stock of 120 film? (I'll travel there this summer, so I might need to visit one if I run out of film)