Right you are, yes, it was that same message. I suppose what I meant to convey is, "despite the thoughtful safeguards built into Slack, I still managed to screw this up." :) I really appreciate Slack and it is my preferred workplace communication platform, so I hope no one reads my anecdote as criticism of the product. I can't think of any way Slack itself could have done more to prevent my mistake.

As more context, I do remember thinking, "that X number seems higher than I would expect, but maybe we had a lot of folks who signed up for the event that didn't show." I worked at a small company so the size of the company was on the same order of magnitude as the number of invitees to the event (~100). I explained away the Y time zones because I knew some people traveled internationally. I was also operating on very little sleep, so that probably didn't help.