Even VWs, with their dealer only reset, can supposedly have their batteries disconnected for up to 90 minutes without making the car’s computer die. After that, you’re screwed. I got stung on a New Beetle a couple of years ago. It was dead when I bought it. A new battery allowed it to start and run for about two seconds. Reset = $140, after the tow. Some indy shops may have access to the system to reset VW computors by now. It’s been out for a while.
I like Caddyman’s idea too, just in case.