Extended summer travel for work and pleasure had the unfortunate side effect of keeping us away from our ActiveE for 31 consecutive days. We left the car in our garage, unplugged with nearly a full charge. I was happy to find that the car started right up and still had more than 3/4ths of its charge when we finally returned to the Bay Area. I had left a USB phone charger plugged into one of the 9V sockets in the center console, but without a phone attached, so it was still drawing current for lighting a tiny LED on the charger while we were away. An indicator came on when I first started the car to note that there was excessive battery drain while I was parked, but otherwise everything was fine.
After the stories earlier this year about Tesla Roadster battery problems after extended periods of inactivity, I am glad to see that the ActiveE was fine after 31 days. If I have to leave the car for multiple weeks again in the future I'll make sure to take photos of the exact battery level before and after to measure the impact, but based on this initial experience it seems no worse than leaving an internal combustion engine inactive for several weeks.