Argh. Car is moved to a legal spot, but the last attempts to move it last night (or overnight lossage, I'm not sure) left it with insufficient battery power to test my almost-out-of-gas hypothesis. Need another jump, and still don't know for sure what else.
So I may or may not be making it to rehearsals this week, depending on how the rest of this afternoon goes.
1.5 V across a 12 V battery isn't a good sign.
But at least I found out why the truck that had been parked in front of me started up at 10:30 and didn't move until 12:20. (Bad compressor, takes a long time to build up enough pressure to work the brakes safely. The driver said usually 90 minutes, but longer today because of the chill.) I did get the car moved before Parking Enforcement came around.