I'm gonna assume that the paper thing is not gonna happen. And I bet anything the reasoning I have for that IS the reason they will tell you. And that's, how do they (the person at the panel door) know that you got that paper stamped and were not given the paper by any other person?
Anyway, I don't know how Kumoricon does it, but when I was cosplaying Cloud from Final Fantasy VII Advent Children at Sakuracon 2012, they let me put it on my wrist. I was able to just push the wrist area of the glove up a little and you could see it. However, I would think you could easily just take off the glove part way and put it back on after.