Watch your neighbours' houses go dark, and/or their alarms go off? B^>
Yes, indeed, if it's night, then I can check street lights and all other lights in the small valley (other than the solar powered garden lights that have become common).
However, that requires my knowing to check, and quite often I may either be asleep or I may be awake and not know when to look out (whether night or day outage, as far as I can recall, I have not noticed alarms to go off in conjunction with an outage). If it's during the day, I'm still completely out of luck as far as having a way to know, and most of the outages which caused me to want to get batteries seemed to be daytime outages.
I think getting the software addressed may solve all this, but it seemed to me there has probably been some simple way worked out by some storage owners. Heck, I remember talking to someone about 15 years ago who had a huge expensive system and he pointed out to me that generally he didn't know if he'd been through an outage until he checked his logs.