Yah, I am sure people mistype registrations numbers often when submitting them to the Weber site. My guess is that it will just tell you it is not a valid serial number or even tell you it has already been registered. No big deal. I really don't think they will send a couple guys in black suits to your door. I haven't registered a grill lately, but I don't remember it ever saying that you must be the ORIGINAL owner to simply register it.