Exactly. I had a manager who said "Standup with start exactly on time", and stuck to it. And after a couple of meetings with some people coming in a minute or two late and realizing he was for real... everyone started showing up on time.

No need for hacks, just better managers

this is exactly the way to do it. i have a recurring large meeting where the first 5 minutes is ALWAYS "lets wait for a quorum". Guess what time I show up to the meeting? 5 minutes late, of course.