Last year, on a flight from LHR to AMS, they asked for volunteers for payment of just €75 and were swamped with volunteers.

As reported in this thread: http://www.flyertalk.com/forum/klm-f...oaded-klm.html

It certainly doesn't happen as often as on DL. And it probably won't happen on your flight. That was the first -and only- time I had experienced that on KLM.

PS - if you don't plan on flying to London anyway, are you not flying with checked luggage?