Apparently it started with the Edmonton Air Traffic Controllers - they chipped in for pizzas to be delivered to their counterparts in Alaska ATC, just as a goodwill / “thinking of you guys” gesture. Now it sounds like over 70 of the Canadian ATC units have sent pizzas to their counterparts in the US, most recently Moncton and Gander ATC sending pizza to a NY ATC unit.
Buying someone lunch when they’re not getting paid is a nice gesture, but I really feel sorry for those US ATC guys keeping the skies safe, and the other federal employees forced to work without pay.
Would they really care? It’s a free lunch provided to them by colleagues. Heck, if somebody bought me lunch at no cost to me (especially if times were tight), I’d be happy to eat it.