Profile swapping. USB/HDD/Not at all?

Hey guys

Here's a question that I've been searching out on both the forums and google.

I have two Xbox's. One is virgin, and I use it for LIVE and as my primary gaming machine up until last night.

Last night, I turned on my first jtagged box, and almost put my virgin hdd on it. Then I thought, if XeXmenu is going to copy files to my profile, will that get me banned when I switch back to the virgin machine?

So in my research, i've heard people say they swap back and forth all the time, and others say they'd never do it, and other people still, say that you can just swap your profile back and forth using a USB stick.

Is there a way to keep my profile online and still earn my achievements and gamerscore intact. I've done it on a falshed DVD drive.

My box is tagged and running the kinect dashboard (if that helps any)