Collective nouns are grammatically singular, I thought... 
Indeed, but are increasingly being treated as plural.
Some of the nouns now given plural forms of verbs surprise me.
Collective nouns may take the singular or the plural. I have not noticed any tendency in current writing to prefer the one over the other; on the other hand, I have noticed an increasing tendency for writers to get confused halfway through a sentence. "People cannot get it through their head" - presumably the Roman people as wished for by Caligula. "A line of people was making their way through a tent" is another example I read a couple of days ago. Admittedly, this latter is probably the result of wrongheaded desire to apply the word
their everywhere possible for fear of arousing hyperegalitarians.
The naive use of plurals where a perfectly good collective singular form exists is also on the increase. Cannons instead of cannon, etc.
Anent the PC
their, its abuse is now so prevalent as to constitute an epidemic worthy of WHO attention. Theoden as written by Tolkein: "No father should have to bury his son". As rewritten by Peter Jackson's cohorts: "No parent should have to bury their child". YETCH!!! And it used to be that the pronoun for a child was
it. Three guesses as to what's prevalent nowadays.
It it ain't.
