could you be more specific about your itin & equipment. yes, seat assignments get all phuglied-up if there is an a/c swap say from a 320-->319 , 320-->rar and 57-->47 ^^ but it can also happen on a 37-->37 swap as there are 4 different types of 37's. i've had the latter happen many times flying sfo-lax and it can happen even after you've olci'd and arrive at the airport (which is another good reason to re-hatch your bp from the chicken when you get to the airport).