There is no requirement for uniqueness in the provisional
registry. In theory, the original registrant can change
their provisional registration and if that no longer
corresponds to a wideley followed practice of the original
registration then someone else may reinstate the original
registration as a new entry.
Good idea! That is rather similar to my idea that in some
cases where consensus could not be reached, the registry
should list the different alternative views/definitions.
I agree that it's useful to be able to list multiple
registrations for non-standard fields - and perhaps
also to describe variant practices for standard fields.
Keith
p.s. this is starting to sound more like a wild bird
sighting report than the traditional IANA registry.