I haven't been asked for a boarding pass in the Privium line for ages. Last time they asked must have been well over a year ago, and I tend to fly once a week out of Schiphol at least. This applies to both the Schengen and non-Schengen lines. And yes, it means you don't have to fly. I once went through to meet some friends on who were passing through Schiphol, and did not want the hassle of going through immigration and customs. I have no idea whether this is illegal or not, but it's clearly not the intended modus operandi. It's not something I would rely on or try to do very often. The option is there...