Well it may have been. I would never just pull it off the balancer when it does that and move on. I would roll it a couple times to be sure but that's just me, so there's probably a good chance the guy never rolled it again and it wasn't actually balanced. So your theory still holds.The “ glass half empty” guy in me prefers to believe that this was one of the reasons for the high speed vibration. The glass half full dude knows that that is probably not the case.