Having been a ham for over fifty years and having worked most modes of operation, including chasing DX and even satellite back in 1979, I totally agree that working AO-51 can get frustrating. However, if you think the mess on AO-51 is bad, try working a rare dx expedition sometime. Talk about pile-ups!
As for protocols, I think I've read this same protocol discussion in just about every ham mag. and no one has come up with a workable solution that solved the problem. People are individuals and they tend to do what they want to do.
I really wish I had a workable, amiable solution, but I don't, sorry. However, I don't recommend the Frequency Policemen idea, they generally just tend to make everyone more upset and the confusion gets even worse
Now I'll get off my soap-box. Thanks, Merle, AA4QE