In May I flew with my bike in a cardboard box for the first time in many years. Went through Montreal, Toronto and san Jose, Costa Rica with no problems either way.
That said, I really do believe its complete luck of the draw about which workers handling your bike that you get, their mood of the day, if they've been fighting with the wife, are pissed off at the world in general, and/or don't give a flying fudge about anything anyway.
I've always just done my best with thinking when packing of what will schmush up against what when jackass baggage handler is a jackass, pile in the cardboard and foam , and then just cross my fingers.
Ain't nuttin we can do after its out of our sight....