It's going to be chaos to enforce, i feel bad for the GA having to deal with this.

People who buy basic fares are unlikely to travel frequently or well informed about airlines policy. Are they going to create an extra zone for basic economy who purchased after January 25 or people with international connections? They are likely going to put remarks on the boarding pass and rely on the GA to check and enforce it.

Some airlines pay the GA commissions for enforcing luggage rules, I don't think AC has gone this far yet, but that also means it may not be strictly enforced and likely get a pass for being a Karen. (See zoned boarding)