In the Ice Cream Sandwich update to the RAZR, RAZR MAXX, and Droid 4 phones Motorola has added a root checker that can also say if the device has ever been rooted. I’m not sure if this last part is for checking if you rooted ever since you had the phone or if it was rooted any time after the update.
@P3droid and people helping him test have found that in recovery menu it will now say “qe 0/0” if the device has never been rooted, “qe 0/1” if the device was rooted before and isn’t anymore, and “qe 1/1 if you are currently rooted.
While no official announcement has been made, if I was to guess it would seem like this was to assist carriers in determining if people rooted their phones therefore breaking their warranty. This feature allows the stores themselves to be able to tell without having to send it in.