There is a procedure in the owners manual to turn it off, it took me a little while to find. its something like, get in, close the door, put the seatbelt on, turn the key to on, wait for the seatbelt light to turn off, then unbuckle and buckle it at least 5 times in 10 seconds, then turn the key to off. It should chime when you turn it off if you do this right.

thats at least my recollection of it, its in the manual, it was a little hard to find, but it does work and its so much better than that damm chime.

and for the record I wear my seatbelt all the time too, but when moving the vehicle around camp or in the driveway or whatever it can be just plain annoying.

EDIT: User KTM87 confirms a few posts further down that this procedure is correct and does work, yay for correct memory recall!