The use of the full-body scanners at Schiphol is optional. The agents there are not very well-trained about this fact but people do normally succeed in opting out. For example, I succeeded after OHM earlier this month, though I was given more push-back than when opting out in the U.S.
Here is a Dutch government site about the scanners confirming that travelers are allowed to opt out:
http://english.nctv.nl/themes_en/themes-a-z/Security_and_civ...
Thinking of other European countries, in the UK, signs at Gatwick say that if you are selected for a full-body scan and decline to use the machine, you will not be allowed to travel.