I don't know about the Netherlands, however here in Flanders the two level racks might be common but I think I've never seen a bike on the higher level. They're

I don't know about the Netherlands, however here in Flanders the two level racks might be common but I think I've never seen a bike on the higher level. They're just used double spaced, with bikes only on the lower hoops. When they're (half-)full people just put their bikes next to the racks.