but... during this time, even those systems are unreliable so i cant imagine this being of much use as of now.
you're exactly right to point out that the information isn't perfect, by the way. I was just at a store earlier doing some personal shopping and I noticed they had employees counting the items because their inventory system wasn't reliable.
That's just the normal way to do inventory, and has no real relationship to the reliability of the inventory system. There's no other way to account for inventory shrinkage (eg. theft, damage).
During the crisis, I don't see many people clicking "I Can Help", but it would be interesting if you could find a way to solve that. Gamification as others have said, might help, but not sure.
It would be interesting InstaCart shoppers, etc, could adopt this as a way to drive more business for themselves. If they're already out shopping and can identify high-demand items are in stock, a would-be buyer could procure it pretty quickly by starting an order with that Insta-shopper. I haven't thought through that, but it's an idea.
I could also see uploading, emailing InstaCart receipts. You could grep in-stock/out-ouf-stock information from those and timestamp it based on when the shopping was done.