Your lunch meeting goes until 2:00, you take a taxi to La Guardia, getting there at 2:30 for your 4:00 flight and your flight arrives in Seatac at 10:00 EST, 7:00 PST. Half hour to get your bag and get out of the airport, and a half hour to get home, if you're lucky, and it's already 8:00 PST. A late dinner, maybe.

That's without the 3 hour delay or the lost bag that this rule is designed to deal with. I'm agnostic on the rule, BTW, but airlines are awful compared to most other industries in terms of customer service.