I mean, you could say the same thing about HSTS and key pinning. Domain changes hands, but "oops", HSTS was set and the old keys were pinned.
Is that actually a problem? No, it's not. Similarly, as the owner of a new domain, why would I want the old content? The only reason I can think of is that I brought a company outright, or something. In that situation, if I don't want to change the content, everything still works. If I want to change it, and they did something stupid -- like unversioned paths using this proposed flag -- then yeah, I'm in a weird spot. That seems like the most trivial and unlikely of scenarios, though. It requires such a complex chain of events to occur.
I think it's safe to say that malicious usage of the flag is entirely out of scope when considering the validity of it, again, because it requires a contrived situation.
Is that actually a problem? No, it's not. Similarly, as the owner of a new domain, why would I want the old content? The only reason I can think of is that I brought a company outright, or something. In that situation, if I don't want to change the content, everything still works. If I want to change it, and they did something stupid -- like unversioned paths using this proposed flag -- then yeah, I'm in a weird spot. That seems like the most trivial and unlikely of scenarios, though. It requires such a complex chain of events to occur.
I think it's safe to say that malicious usage of the flag is entirely out of scope when considering the validity of it, again, because it requires a contrived situation.