The car that DumbMike opened the hatch on was probably left unlocked by who ever was driving the car. The Prius FOB uses a rolling code that is unique every time you open the door/hatch. So it would be just shy of a miracle if his FOB matched both the pin code and rolling code in the other car. If it did if I were Mike I would be headed directly to Las Vegas and the nearest craps table.
You don't have to do anything to keep them in sync. The computer takes care of the problem. If you lose all your fobs then you are in a world of hurt. Because Toyota will have to replace the ECU and the fobs as you need at least one of the original fobs to program a new fob.
A couple of months ago I saw 3 G3-I at a local dealer. All three were super white (just like G2 super white), not Blizzard Pearl. They were a fleet purchase for a single buyer. Keith
How does the computer keep them in sync then? (which is, of course, what I meant) Here are things that need to be accounted for: 1) The button on the fob may be pushed when the fob is not near the car. 2) The battery in the fob may be removed or go dead for an extended period. 3) The battery in the car may be disconnected. 4) The fob does not contain much processing power. 5) The system must add significant security over simply sending an id.
I'm sure the owner left the car unlocked, which allowed me to open the back door. I love playing craps in Las Vegas. How did you know? Mike