However, new fobs use rolling codes. Youll likely get it paired, use it once, then when the code rolls, you end up deauthorizing your fob because it is behind on rolling code. Sometimes itll work for a few uses, if you have multiple keyfobs (it has to do with how the vehicle, Fords in particular, handle the way code is used) but YMMV.

Old school keyfobs work, tho. Garage doors are much the same.

[–] reluctantpornaccount@reddthat.com 2 points 2 years ago

Even new garage doors use rolling codes, for exactly this reason. People could break into houses with a flipper and a little patience.

Cloning a fob that has rolling codes, and then using it to unlock the car, may de-auth the real fob and lock the person out of their car until they pay (sometimes $$$) to get it recoded. So, unless you have actual malicious intent it's a pretty shit thing to do.