What's the legality of devices intentionally violating wifi standards and causing potential issues with other devices? Is this something the FCC could act on?
Usually large vendors try to do the right thing.
So long as you're complying with the general rules for the ISM bands, I'd expect the FCC doesn't care about you following the details of a specific protocol.
As to what that exactly means, and where the line is drawn is up for debate. I doubt Apple would necessarily lose here, but ‘wifi jammers’ on Amazon would, for example.
It's in-scope for the WiFi alliance, but I don't see this as "poking" them. It's either a bug, or it's a way to get your devices to work a bit better than the competition, but in a way that the WiFi alliance would never notice.
47 CFR § 15.5(b): “Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused and that interference must be accepted that may be caused by the operation of an authorized radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator.”
47 CFR § 15.5(c): “The operator of a radio frequency device shall be required to cease operating the device upon notification by a Commission representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected.”
47 CFR § 2.1: Harmful interference: “Interference which endangers the functioning of a radio navigation service or of other safety services or seriously degrades, obstructs, or repeatedly interrupts a radiocommunication service operating in accordance with this Chapter.”
If you somehow adjusted the definition so that this would count as harmful interference, then every competing service would also count (microwaves, bluetooth, baby monitors, 2.4Ghz cordless phones, even other WiFi, etc.).
Intentional interference here doesn’t mean ‘slightly tweak behavior from a given standard’, it means things like ‘intentionally create nasty interference to block other users’ or ‘recklessly spam the band with enough noise no one else can use it’.
Notably, most cheap IOT wifi devices already do massive spamming of the band and terrible behavior that makes it nearly impossible for other users of the bands to work well, and they aren’t getting in trouble.
See everything from cheap Wifi security cameras to ‘smart’ fridges.