peter,

yes, i did. acutally i think the guarantee is not for intra-german flight, as long as LH did not change their policy. anyway, i was able to reserver last week for three days. i just booked the most overbooked flights (the one arriving HAN before 9 and leaving HAN after 6:30) from/to FRA. Was waitlisted at the travel agency, after calling SEN service I received my confirmation immediately. Neither travel agency nor SEN service ever doubted I could get on this flight.
As of now some A320 services are upgraded to A300 -- and I am sure 90% of the PAX will be SENs
I have tried to book flights to CeBIT two weeks ago for a friend from Taiwan and the leg FRA-HAN was just not available; waitlist closed. Anyway, use your SEN card and I am sure you will be fine.
BTW, ScottC also told me about the 75 Euro heli service from the airport to the show which I just booked for all three days and which seems to buy me some more valuable time on the show.

Back to the topic: No more of you going to CeBIT? I am there Friday, Saturday and Tuesday -- would be happy to be part of some FT lunch! Or anyone on those flights?