It's probably around the same in "normal" cars today. If you just have a car in park it won't move until you move it out of park, the catch is in gas powered cars, even if the battery is dead you should be able to put it in neutral to get it towed. In electric cars when the battery is dead, well that's all you have, so you can't get the gear into neutral to make it at least rollable.
Towing shouldn't be a problem, tow trucks carry dollies that can be manually inserted under tires. It takes like 5 minutes. I guess there are probably some limits on speed and range.
Sounds like a design failure with what little transmission the roadster has, at least with the parking prawl not having some sort of mechanical deactivation.
