Run Them Right
Too many people casually run meetings pass the allotted time. Keeping meetings to their scheduled length should be required.
There are three key reasons:
It forces organization. Effective meetings require a clear agenda and objectives. If all meetings have a hard stop, organizers will need to learn how to plan thoughtfully and orchestrate meetings appropriately. With thoughtful planning, unforeseen discussion topics are less likely to hijack the agenda. If they do, then schedule a follow up for the sake of ending on time.
It's a practice in keeping your commitments. When a meeting invite is sent, the organizer commits to an agenda and time. Violation of commitments, no matter how small they seem, breach integrity. If let go, the organizer will make a habit of meetings running long. The same applies to meeting deadlines or any other commitments. Commitments should be taken seriously.
It signals to others that you respect their boundaries. Meetings that run long show a lack of consideration for the other person's time. Even if you ask them if they have time to stay late, they are not in a position to freely decline. It is best to assume they don't have time or that they would rather have the meeting end on time.
Meeting organizers need to be responsible. Their job is to ensure the meetings are focused, inclusive, and respectful of participants time and attention. If this is not happening, fix the issue right away to start achieving the benefits above.