There is a document possibly by ICAO, Eurocontrol or the UK CAA that explicitly says what I outlined above. If someone can help identify the source that would be great. The 50% who believe the altitudes must be respected need to understand one thing. The point of an altitude restriction is to ensure clearance from terrain or traffic on other routes. If you are not on such a route, then clearly those exact limitations do not apply. And what exactly is the answer then? To guess or eyeball the level restriction each time? That would leave a lot of room for interpretation which isn't how we fly. I believe such pilots generally hail from from Asia or Latin America where I will admit, local rules could be different because the ATC isn't standard.