Way more than once.
Last time was a couple years ago when I was looking for a Roger Clemens Blue Streak error. Saw a buy it now that was just listed with 18 1986 Topps Clemens cards listed and there was a Blue Streak error in the lot. Cheap price so I hit the buy it now so no one else could buy it before me.LOL
Then when I read the description the seller clearly stated the Blue Streak error was not included and listed separately
Anybody need some 86 Topps Clemens cards?