I just flew to Sydney from Melbourne and took my Brommie with me. I decided to deliberately not bag or pad it in any way to see how it would come out the other end. All I did was wrap a luggage strap around the whole to keep it well together, and tighten the hinge clamp screws to prevent them from falling out.
So here's what happened:
1. Arriving t the checkin desk, I was asked what that was, and I said, "Bicycle." Mistake. I said I wanted a Fragile tag which she attached.
2. She looked at it, hesitantly fetched a big tray to put it on, and noticed it wouldn't fit in the tray.
3. Call supervisor, "There's a customer with a bicycle here..." Supervisor came over, looked at the small package (for a bike) and said, "Sir, we have bike boxes, you don't have to disassemble it like that".
4. Explained it's actually a folding bike, it's not disassembled. Big surprise and friendly interest.
5. Some more looking, some talking over a walkie talkie, then, "Sir it's got to go into a bike box. We sell these for $15."
6. I insist it's no bigger than a standard suitcase, it's only half the weight limit, it's no different from a stroller, it's absurd it must go into a box.
7. Some more humming and staring at it, then, "Sir this sticking out metal bit will damage the aircraft." Points at right pedal.
8. She repeats herself, I repeat myself, several times, each time a bit louder than before. Finally she seems to hear me and decides it can go as-is with the oversize stuff. Even though it is not oversize.
9. At the other end, the bike waited for me at the oversize stuff again, the only item.
Damage? The two hinge screws' thumb levers were bent. Both of them. The wheel rubbed against the mudguard. Otherwise it was fine.