On a recent flight to Cyprus, flown by KLM to Prague and then Czech Airlines to Cyprus, my partner's ticket was checked by the KLM people before boarding. only later to be sent back to Holland because the Czech Airlines stewardess in Prague, the official partners of KLM by the way, said she couldn't read the Dutch on his official papers (he is a foreigner, staying legally in The Netherlands with all the correct papers for it).
KLM have done absolutely nothing about it, saying that they have contracts with their partners making them responsible for dealing with claims. All very cute: take the money, and when things go wrong, leave the customer stranded.
Needless to say, Czech Airlines have not even had the decently to respond to anything I sent. Czech Airlines has always been known in Europe as a third rate airline, but as a regular KLM passenger, I am extremely disappointed with KLM. Now that they need money, they are making everyone a partner, but beware when things go wrong because you will be stuck with the results.