My husband is traveling home with son after packing him out from college. At the airport, he checked a cardboard box (sturdy & properly taped, I'm sure) along with other luggage. TA (United) scolded him at the airport, saying cardboard boxes are no longer approved as shipping containers and the airline will not cover loss or damage.

We have checked boxes before without incident or notification of such a policy - is this a recent change? I don't know if he had to initial/sign a damage waiver this time; we haven't previously. Or is this a rogue TA? I'm sure the fallback response is a security concern (TSA inspection time).

As it wasn't disallowed by the TA, I don't plan to stop checking boxes when needed. However, if this policy is really the case, I will consider what I put in a box that I would be checking. Buying a suitcase or other container just to satisfy this policy seems outrageous if it is something I can put in a box and still be within size requirements.