You're trying to screw burnside out of what, like BTC0.007-BTC0.008? Not only that but you're exposing yourself and whoever trades with you to a significantly higher risk (one of you not delivering) in order to save less than $1.00... Good luck...
I honestly don't mind -- but you'd have to be crazy to do this for anything substantial because of the risk that the other party won't follow through. If bad things happen, please don't expect there's going to be anything I can do.
Cheers.