dr
I have seen a couple of examples of how some people at the "competing site" are marking their bills. I think the way they mark may be the reason some of them are getting high hit percentages. When I get a chance to do some scanning (hopefully in the next couple of days), I will show you how I mark my bills versus how they mark their bills (and I will reiterate this message).
Now I can't control how you mark your bills, but I would ask that you do it by writing or stamping in areas that are non-intrusive and don't ruin the bill, per se. I, for example, write in the small 0.5 cm space at the top of each bill (both on the front and on the back). I'm sure you are all marking with respect, so this message is mostly for the newbies.
Have a great weekend,
-dr