I never pre-book assistance at airports - I prefer to do things myself and in my own time, making sure the connection times are 2+hours (or even longer at Schipol). If I had pre-booked assistance things may have been easier. Now I am getting older and less mobile, I will probably do that on my next trip. To avoid the any stampede, I do ask for priority boarding when arriving at the gate and always wait for everyone else to get off the plane before me. The only other assistance I ask is for an attendant to carry my bag when embarking/disembarking (assuming it is steps to the plane) At Schipol, I can manage the buses ok, but on this one occasion they insisted I wait for a disabled transport vehicle and a wheelchair, saying it would be quicker!
You are right that it queue-jumping is possible in a wheelchair and it may help me avoid the dreaded customs officers too! The fact that I travel alone means I am a target for customs officers - especially when I am the very last passenger to collect their luggage!
Oh I don't see it as queue jumping Howerd, I think that it is perfectly ok that people who have so many other things consuming their time, just trying to get by during the day, get a chance to save a bit of that time when they have to travel.