Let me make this easier for you... instead of paying money to find this out through Rebel's live chat, simply put your iPhone into airplane mode and then sync. That's all you need to do. Now if you ever restore your cell, you will need the original sim in your iphone because of when the phone reboots at the end. It will lock you out and you'll need to reactive it. Not a biggy, you just need to know this can happen.
My problem, incase anyone can help... I have lost battery life on my iPhone dramatically! I only get 6hrs. standby now! So I can't even use my iPhone anymore. This is with the screen turned down to 25% and everything turned off. All I'm saying... it happened after using Rebel Sim. And even if I take the sim out... it still remains damaged!! So please let me know any solution and if you are trying Rebel - be careful! But everything else concerning Rebel Sim worked magically!