Thanks Robert. I'll change my advice regarding freezing sheet film! I used to have problems with sheet film sticking in high humidity, but that occurred whether it was frozen, refridgerated or left at ambient temperature. I wonder what the mechanism is - ie how freezing makes the situation worse. Thinking aloud - the moisture could migrate out of the gelatin as the temperature falls, to collect as a thin ice layer on the surface of the film.
That is when mailers come handy, I normally send them out as soon as I shoot them, hot off the camera. When I am back home from my vacation/shoot I already have my slides waiting for me at home.