Interesting post.... You can do a little research if you care -- anecdotal evidence you might pick up here is pretty much worthless.... I happened to own some Feb. 12.5's, and I watched the tape even more closely than usual, including a 4:00 "print" of 12.50 on the button, up a nickel from the prior print, where 99.9% of the movements during the day were 0 cents or 1 cent.
Of course, when someone in the After Hours market (around 4:17 if memory serves) put 500 shares through at 12.55, I was VAGUELY tempted to try to make the 4:30 deadline.
My instincts are that there was too little REAL money to make manipulation really worth it, hence likely, but I could be wrong. Obviously, the stock had a pretty bumpy week or 2 and the fact that it started the day within a dime of 12.50 may (I suppose) have made a little game-playing more likely as a result.... I also own some 12.50's in a future month, so I hope either this is something like coincidence or we're nearer 15 or 17.5 when their e-date rolls around.