AMS Schiphol is my home airport. It is an airport with a pretty tight security. Things we are more relaxt in are stuff like medication, vegitation etc, but travellers safety? Hell no! ;-) I always have to be padded down as I'm a wheelchair user and can't walk through the check ports. Let me tell you, I've never been 'padded' so rigorously as I routinely get at AMS.
AMS is the only airport in the world asfaik at the moment that actually has got body scans that can do security checks for any items carried on or in the body without needing a human operating the scan (and thus seeing the persons body while being scanned). Those scans aren't being operated at the moment, as society at this moment finds it to be too violating of individuals. Those scans are to-tal-ly not my idea of what security should look like, but it does go to show imho how important Schiphol tends to take security that they are already there 'just in case'.
And this all still is talking about basic level of security. Now, when flying to the US? You get another nice check before you are able to enter a secured gate waiting area. Of course you'll have to do the security check again if you leave that holding area. While we are being told this is 'standard asked for by the US', I've seen airports do without these checks.
First thing AMS did was state they didn't know what happened and until they would, they wouldn't disregard any option. I found it refreshing that they didn't put together a pressconference right after hearing about this incident and stating "whatever happened, not our fault". Nothing of the kind, except -yet again- tightened security checks started right that same day. Since then, the US and FBI have informed AMS Schiphol and Dutch gouvernment that there was no blame being put on them, no security breach had been found so far. Not a position I expect either to take if they suspected otherwise.
Besides this; it can depend on the airline which further checks are done. To give you an idea; of course I get checked at AMS. My manual wheelchair (which I gate check) gets checked. My powerchair gets checked before being loaded and that's it. Or that's it when it comes to NWA, UA, KLM, MA, SA and LH at AMS airport. Not so with CO. Besides all of these checks, CO also pulled me out of the gate check line to ask me all kinds of additional security questions about the chair.
EU as a whole tends to be a little brother when it comes to the US. Like a little brother, they can have the tendency to want to do what big brother asks to get on brothers good side. To my own puking, the Dutch gouvernment tends to want to be the best boy, so whatever the US asks, suggests or even hints; our PM will bow and say "Yes, mister president". Same thing goes for airtravel security. As such, the security check at the gate for US-bound flights are stricter than any other at AMS than perhaps ElAl flights.
Is AMS airport infallible? No. Like any other major organisation in this world that has to deal with anything, Schiphol isn't infallible either. You wouldn't want to hear stories many that fly can tell you about airport security all over the world, also within the US itself. Never mind what we do, if somebody is determinated enough they will find a way to blow up an aircraft, crash it, whatever they fancy. It's a cat and mouse game.
As always; this is a situation from which all involved can learn. Learn, which I hope will not turn into being dominated by angst or blinding ourselves with wrong sence of heightened security being caused by the pants-wetting-funny new regulations like no flight map on international flights into the US. If we think these things will even make one terrorist go "hmmm, maybe I shouldn't be doing this", we have a MUCH bigger problem than the real problems this world has got.