Chris Brown -- Mannin' Up to Drop Off GF Karrueche ... Guilt Trip or Nice Guy?

Chris Brown was caught at LAX doing the deed with Karrueche Tran ... being a good boyfriend, that is.

You know it's true love in L.A. when someone goes through the hassle of dropping you off at the airport -- that, or your spirit's been completely broken. Or you're making up for something. Whatever the reason ... Brown did his duty giving KT the kiss and fly on Sunday.

This is huge, when you consider he could have just sprung for an Uber -- but she still lugged her own bags. He's good ... just not THAT good.