See this post for related discussion

How seriously should I take size and weight limits of hand luggage?

I'm interested in hearing anecdotal evidence from a specific airline and airport.

Flying KLM

AMS Schiphol ---> JFK NYC

Is there any precedence of KLM weighing carry-on bags at Schiphol? I am planning to put my textbooks in my backpack to decrease the weight of my checked luggage to its accepted limit.