That was the other part I forgot to add.
Ive seen a partial 'roll'. I believe the roll is two inlays wide, ie front and back.
So aside from the fact the process would never allow for an odd inlay to appear in the roll, the only way such an error could occur at the factory is if the whole roll was applied to the wrong chip.
In that case, I find it impossible to believe the job would be completed un-noticed, and they would know exactly how many rogue chips to look for during quality control.