my wii remote from time to time get unsynced. when i first got it (it was presynced with the wii already, the remote it came with) and i got another remote, my boyfriend in his infinate amount of wisdom attempted to use the power button and mess up the syncing between the first initial remote! took me seriously 10 min to figure it out and i was highy aggrivated.
second time, i packed it in my carry bag to a friends house and i guess the buttons pressed in the bag and it unsynced again.
its highy annoying from time to time