If you hide it they can't change it

oh it changes automatically, and often, which is the problem. We have a field on Employee that’s “Last Slack Status” (either online or offline). I have a scheduled script that pings Slack every 15 mins to see whose online status has changed, and updates the field in NS accordingly. We use that checkbox to know which employees to indicate as “online” in our “Contact Us” page on our site.

I've searched the system notes like 1 time ever so I don't know that much about what else you'd be searching for. Your solution seems valid at least in terms of setting a field on the record for status. I can see where that could clutter up the system notes. Could maybe modify it so that every Employee has a custom Record "Slack Status" that you update instead of the Employee record. Your solution would then read the slack status (join to it) and then you won't be showing a ton of updates in the system notes of the Employee.

Yeah, I was already thinking that might work better