I agree, this stinks of petty gotcha, which is why i dont think its a good idea, as remaining employees with devalue those perks and stop working for Meta as a result.

And yes, these are perks above all else, but remember Meta created these incentives to keep people in the office longer without having to pay them (a lot) more. A few people abusing it in order to ensure the majority of workers stay nights and weekends (at small satellite offices) is a small price. Now? "Hey, worker X, staying late tonight?" "No, going home to eat, don't want to make a mistake on ordering Uber Eats and get fired" means you don't get 5-40 hours per week extra time from that worker X. And you already paid for the vouchers, so you don't save money. Also other workers won't stay because more people leave.

Granted we are talking Mark Z here, so eating food is probably too alien for him to understand.