I just tried to check in a bunch of pax on KL887 AMS-HKG.
If I take the PNR/Flight # route, I get a message "you have already checked in", without a possibility to select/change seats, or to print boarding cards, or do anything else.
If I log one of the pax in with her FB number, KL changes its tune, and I'm now told two things on the very same page:
"It is not yet possible to check in for this flight. Please try again later."
and
"You can check in on Mon 09 Dec 2013 11:40"
That was almost 5 hours ago!
Oh boy!
Johan