However, I'm under the impression that card issuers normally tell
customers that closing an account does not block payees from using
continuous authorisations in the future, and that they (the issuers)
can still bill customers for such charges made to closed accounts.

My card issuer gave me a new card number specifically because I told
them an online retailer was likely to payment from the old card and that
I hadn't authorised the payment.

The retailer duly did as expected, and the transaction failed.