I know this is an old thread but I wanted to respond in case it helps anyone who comes along.

I have flown Swiss with an Impact collapsable crate with the Impact Collapsible Bracket (IATA) installed. Swiss is owned by Lufthansa and appears to share the exact same crate size requirements, web page form, pricing, and therefore I would assume, policies, as Lufthansa.

I have travelled twice with this crate from SFO <-> ZRH. The personell at SFO and ZRH were intriqued at the fancy crate, but none of them seemed to have any awareness of the "non-collapsible" IATA requirement, just polite and friendly chit-chat ... and so I didn't get the third degree. I think if you catch a cargo employee on their bad day, you might not get so lucky. But technically speaking, the IATA bracket kit makes the crate non-collapsible by definition, so it might end up being a "I'm sorry, but I respectfully disagree. Is there a manager or supervisor I could speak with?" and try to argue your case.

When I fly with pets, I always buy the "flexi-saver" tickets that allow for re-booking, because there is always some gray areas that must be skirted, and I figure it's just a matter of time before someone says my water container is too shiney, or the crate's airholes are 1/2 mm2 too small, or sorry the plane's cargo hold isn't working, or the USDA changed their requirements again, etc ... and I have to address the issue & re-book