ClickOnce related questions at MSDN Event in Boise, ID

We had a fantastic event in Boise, ID yesterday. I left the venue with a few questions I couldn't answer immediately about ClickOnce. I found this FAQ to be EXTREMELY useful :

https://www.windowsforms.net/FAQs/default.aspx?PageID=1&CategoryID=24&tabindex=2

I wanted to clarify one thing about "mandatory updates" that a customer had yesterday. I was unsure as to how mandatory updates can be enforced. I've seen this tab a zillion times but didn't know how to get to it yesterday - I suppose was starting to blank out.