Using Classic Outlook on Windows for personal email, calendar, and contact management
Well, it turns out that I was a overly optimistic. Today I had a couple of icons graciously shoved back on the inbox ribbon by the all-knowing managers of Microsoft (they obviously were quite sure that I had removed the icons by mistake and desperately needed them...). Fortunately this only happened on the inbox ribbon, none of the others were changed (for now).
Nevertheless the frequency of MS invasiveness is MUCH lower than before so I'll keep the registry item for now and keep the form updated
The other thing I've done to 'lock' my ribbons is make the .officeUI files read only in this folder: %localappdata%\Microsoft\Office
This is the most important one to lock:
Main UI - olkexplorer.officeUI
The other ones you might want to try locking are:
Calendar Item - olkapptitem.officeUI
Contact Item - olkaddritem.officeUI
Mail Appointment, Responding - olkresponseread.officeUI
Mail Meeting Requests - olkmreqread.officeUI
Mail Reading - olkmailread.officeUI
Mail Sending - olkmailitem.officeUI
When I want to make a change, I take off read only and make sure I put it back after I'm done.