This is one reason I would always reprint your BP at the airport. This way you can know a little further ahead that your seat has been changed and if you have time bring it to the attention of the folks at the medallion desk. It does seem like re-printing your BP at the airport negates the effeciency of OLCI but it 30 seconds it takes to walk up to a kiosk and reprint can be well worth it. If you've received your medallion bag tag and/or key-fob these can easily be scanned at the kiost for a BP reprint or even for full check-in.