"If you do that, your own kit performs de-auth against any nearby clients trying to join those networks, which results in only "your" networks working and everything else literally disconnecting for everyone within seconds."
If anyone complains to Ofcom (or the FCC if you're in the USA) you'll find yourself in for a world of hurting. It's classified as deliberate interference and penalised as such.
If they're spoofing your SSIDs then it'll probably squeak past the lawyers but actively interfering with anything else is on extremely dodgy (and expensive) ground. Ask the Marriott chain about that.
(I have the wifi network here setup to log those SSIDs in use and reconfigure the network so that nearby access points jump to other channels. After that it's a matter of taking a walk to the location and having 'a quiet chat' with whoever's operating the rogue AP - which is almost always a phone unintentionally left in tethering mode.)
In the UK, DEAUTH attacks additionally fall under the Computer Misuse Act, which has a lot more teeth than Ofcom. As the admin, I really wouldn't want to risk personal prosecution for activating that "feature" on our APs.
Biting the hand that feeds IT
