[jerf]

My local energy company has a website where you can register an account to pay remotely with them. I have uMatrix on and it was blocking some third party scripts. It managed to get my account into some sort of "half-created" state. It is impossible to log in, impossible to reset the password, and impossible to create a new account with my (physical!) address because "an account already exists for that address". I ultimately found another solution, but that's the worst breakage I've ever seen... not just that my payment didn't go through, but my browser config permanently scrambled the entire possibility of ever getting an account set up!

(I did not bother trying to explain this to a human on the phone, because of the aforementioned alternate solution. That just sounds a supersized order of pain.)

[shadowgovt]

That's a bad bug on their end. It implies that if a user's user-agent crashes (or they kick the power plug out of the wall at the wrong time), they can get into this state.

As a general principle, it should be impossible for a client to "half-configure" an account; the Internet isn't designed to be reliable enough to support guarantees that all the relevant messages get sent and received.