Today, we have many, many people merging PRs directly in ways that (often unintentionally) bypass the "tree status" check:

• Wait until all scripts are loaded in the page before running main for the DDC library bundle format #162707
• Roll Dart to Version 3.8.0-70.0.dev  #162691
• Skip web hot reload tests that test execution for all platforms for now #162682
• Make CupertinoSheetRoute usable with Cupertino(Sliver)NavigationBar #162181
• Simplify hash table iteration. #162483
• Fix warnings on startup about display monitor #162653

... in fact, it's easier to find PRs that ignore "auto submit" than PRs that use "auto submit".

This is sort of our own fault, we can't control the UX of Github, and a giant green button that says "Add to Merge Queue" is never going to be understandable as a "Actually, Add to Merge Queue in a way that skips Tree Status Checks, so Probably Don't Do This". We should start treating "tree status" as a required check, ignoring it only for emergency labeled PRs.

I am marking this a P0 as we should mitigate this ASAP, we've just gotten lucky so far it hasn't meant cascading breakages.