Found addtl. info on KLM.ch's transfer form for the comp offer (now also till Feb15):

This offer is for top-level members only - Flying Dutchman SilverWing and RoyalWing and their equivalents in other programs

Full text:

Participants must be older than 2 years and reside in Europe, Africa, the Middle East, Latin America, the Caribbean or the Indian subcontinent.
This offer is for top-level members only - Flying Dutchman SilverWing and RoyalWing and their equivalents in other programs.
Applications without an original statement cannot be processed.
Members can apply only once.
The six-month period for qualifying starts on the date on which the form is signed.
Retroactive credit is not possible for flights made prior to receipt of the membership card.
All awards and benefits offered are subject to change and availability.
Members, irrespective of level, who do not obtain the minimum requirement of 10 one-way flights or 7,500 service points will receive a BlueWing membership card after 6 months.
All members, including RoyalWing members, who make between 10-20 one-way flights within the first six months will receive a SilverWing membership card and a credit of 50% of the free award points.