Thanks all, that's pretty much what I assumed, knowing other cities with multi-airports do have a generic city code. Having originated from BER (TXL) maybe it was fitting they used YTO. Interestingly, in watching most of all the bags come down the carousel -- my two bags were tagged with those red STAR priority tags, but one actually arrived with only a German security inspection tag and no airport designator label (removed, came off?) and the other was about the last off the flight with its label and red tag intact -- mine was the only one not marked YYZ.