Well, how bout dat.As you mentioned, racking can be a large issue. If the balls are fairly old and the room has to replace one of them, a tight rack will be hard to get. If sets of different ages get scrambled, good luck.
As for position play problems, here is an analysis I did in my December, 2005 column in Billiards Digest -- at the end of the PDF. For the range of ball size errors we actually saw in that room, the difference is significant on draw shots.