Dear Gwatch;
You are right but it has something to do with the new technology, once the car is dead the ECU needs to reset and in old car they were right underneath the steeriing wheel but in newer car they have chips / code in the key which is not recognized. Once the battery is dead again they have to bring it to the dealer or a mechanic who can rest it or  by pass it. As  I talked to the young mechanic he told me that i have to find out the ecu and pin it for couple seconds it will reset the ecu and will start it. I think there may be more advise how to do it.

I saw an ad  on web regarding new key that will bypass the codes. How aobut in your 2003 camry xle?