Like I said, if it works for you..
I'd be more worried about the rat peeing on me, my clothes or the carpet while I transported the ball of "snake wrapped around rat"! I would think the rat probably pees pretty quickly once grabbed. I know I'd pee my pants if a giant snake constricted me
I'd rather clean up a bit of rat pee in the enclosure next day, rather then off of the carpet or myself. Not to mention its not ideal to put the snake through this. They know they are the most vulnerable during constricting/feeding.
But perhaps yours don't mind
edited to say: be careful you don't actually startle the snake enough to loosen its grip some. Could result in the rat delivering a nasty bite around the head/eyes of the snake..