Just this week I got a $100 note that had peculiar 'tactile features'. At first glance, I thought they were grossly misplaced and potentially a true error note. They mimic the genuine bumps in size and grouping. However, the appropriate features were there too. The real giveaway that someone had been messing with this note, was that one set of extra bumps was on the wrong side. I hope that no manufactured errors like this show up on that certain auction site.