Usually when arriving from a non-EEA country at Amsterdam, you are waved through the customs check after collecting your baggage at the carousel. (Unless you look dodgy!)
Unfortunately Schiphol's been in the media recently for their overhaul of their Central Security Screening procedure. More bad news is hitting them this week. According to NL Times, On Monday 6th July, the customs officers will check ALL arriving passengers. The article does not mention a specific date (or more correctly, the one they said has now passed), though this Privium Facebook post seems legitimate enough.
While I can't completely understand the corroborating Dutch reports, given I use Google Translate for the most part, it appears to be as part of a protest on their labour union terms. If you're arriving into Schiphol tomorrow, don't forget to take pictures and maybe even tag @ptbmade if you tweet it!