ML should allow to change (or remove) the link to Google Play:
Accidentally I have linked ML to a Google account that I'm using for a specific device (for backup purposes).
As this smartphone is no more operational (RIP, sic.) I should be given the option to delete the link ML -> Google Play.
After removal, I could then link ML to the correct Google account.
Notes:
- The link is maintained in ML data; removing the link to ML in Google Play does not help
- To avoid abuse (I can't imagine how), removing to link could be possible only every 6 (or so) months.