Is this usage of "whoever's" acceptable?

Question

This question sparked a long conversation in the ELU chatroom and I figured the crowd might have some additional insight.

Is the following sentence correct?

Whoever’s car is blocking my driveway must move it immediately.

When discussing fused relative clauses, Huddleston & Pullum (2002) mention this sentence in the following footnote (p. 1075, n. 17):

The genitive forms whosever and (informal) whoever’s are possible but rare in the free choice construction. Thus "Take whosever/whoever’s you like" could serve as a response to the question "Whose bicycle shall I take?" The genitives are not admissible outside the free choice construction – cf. ∗"They want to question whosever/whoever’s dog was barking throughout the night" or ∗"Whosever/Whoever’s car is blocking my driveway must move it immediately." The close grammatical association between the genitive determiner and the following head noun seems to suggest the anomalous meanings where it is the dog they want to question and the car that must move itself.

They say that the sentence in question is flat-out wrong, giving it an asterisk instead of the question mark they use to indicate marginal acceptability.

But most of us in chat thought that it was acceptable, albeit informal. H&P often focus on British English and fail to note differences between it and American English, but I'm not aware of any dialectical variation in this usage of "whoever's." It could also be that this usage has shifted between 2002 and 2023, though that seems unlikely.

So, is there a reason why intuitions differ on this issue? Who's got it right?

Note: This is not a duplicate of this previous question, which concerned how common these forms are (and whether "whosever" is more correct) rather than their potential syntactic roles. This is also about fused relatives, not exhaustive conditionals like "whoever's food this is, I'm taking it."

Answer 1

There are a few examples in the Corpus of Contemporary American English, though all but one rather questionable example are post 2000. Perhaps it is becoming more acceptable.

Her coworker has been given the same assignment, and they're both scheduled to present their separate campaign pitches back in Philadelphia after the holiday. Whoever's pitch is chosen will earn a major promotion. But the day Marissa is set to leave Hawaii, her hotel room is broken into, and her purse is stolen. Without any identification, she can't get on her flight home. (Cosmopolitan; Officer Naughty; Dec 2009)

Whoever's ox Obama chooses to gore will probably be a considerably less enthusiastic coalition member come 2016. (the Daily Beast)

Maybe he got greedy and started skimming. Whoever's money it is has to know Tommy. I didn't see any Fortune 500's in his address book. (TV; Law & Order: Criminal Intent; Consumed; 2004)

Janet Flannel is not easily extricated from under the sternum. where she helps me become a soft touch. clearly must have been someone they trusted. the evidence in bleeding, nervousness, erratic behavior in the pasture. whoever's brain is highest in coherence dominates. do you believe this? (Kenyon Review; Fall93, Vol. 15; Robinson, Lou)

In fact, whoever's money it is returns a few hits on a google search where it's the person, not the money, that's referenced.

At some point in the next month or so, Whoever's money it is will be calling the bank, The bank will then start the track back to find it. They will then pull it from your account. Just pretend its not there. If in a year its still there then its yours. (forum)

Tax is declared by whoever's name appears on the T5. (forum)

But they'd have to be scared whoever's money it is would come after them. (An Unfortunate Place to Die; Allan Taylor; 2018)

Perhaps these are all ungrammatical, but they sound alright in passing to my ears.

Answer 2

Whoever's car is blocking the entrance has to move it immediately!

is what I'd expect to hear over the loudspeaker at any venue in mid-Atlantic USA.