Oz, (or any other merchants out there)
Just out of curiousity, what's to stop the following:

You and I are friends and in cahoots. I let you (your company) charge X amount each month. You then write me a check for 98% of what I charged. (98% or whatever would cover your fees from Amex.)

I use it to pay off the charge, and the cycle starts over. Especially if I could get 1.5 miles to dollar -- I could really clean up.

Am I missing something obvious here?

-levi aka eastwest