Fears of intereference between consumer electronics -- even wireless devices and cellphones -- and aviation electronics are overblown. There is a possibility that some devices might interfere with an airplains communication/navigation gear. Maybe. It'd be easy enough to test that out and only ban the (probably very few) devices that actually interfere, but between regulatory turf issues between the FCC and FAA, airlines' fear of lawsuits and (probably) the potential for deriving additional revenue from 'airplane safe' devices/services have prevented anyone from doing so.
Truth is, pilots do, in fact, use cellphones while flying right now, and Robert Cringely has experimented with WiFi in the air as well. See his articles on the issue here and here.
Also, I've been flying both internationally (Europe <-> US as well as within Europe) and domestically for years, and rarely have had much trouble with shampoo bottles and the like opening up from pressure changes. It's when they're checked and get squashed in a softside bag in the cargo compartment that things usually get messy.
That said, I always pack the wet stuff away from electronics and wrap the bottles in a plastic grocery bag or similar to be safe.