The last time I tried Zoneminder, the problem I had was that the detection algorithms were so bad that I found them useless.

Fair enough. I've had them set off by deer no matter how hard I try to avoid it. I think they know they are getting my attention.

For what it's worth in a school setting there can be monitors in multiple admin offices, the admin waiting area, school police office and other offices to group source monitoring of strange activity. Otherwise if nothing else it is useful to be able to go back an hour, a few hours or days to verify the "he said, she said" accusations often uttered in school.