[alt227]

How is this possible for any normal person with a work provided 365 account?

[Terretta]

You can use the +label method on M365 work accounts, like [e-mail]

Outlook rules match on them too, for rules.

[alt227]

All companies know this and it is trivial to strrip the +label from the address automatically.

If you are using +labels on your addresses and think you are being clever enough to spot companies that sell your data, I can tell you I have personally seen companies use code to strip these labels before selling profiled data.