Hi Norwegian. There is no policy as such where I work about direct routes. If possible,then some track shortening will always be given,ATC is there to provide a service after all.A lot of the time however it is not possible and for reasons that may not be obvious to the pilot, hence why you may be on a very quiet frequency and wondering why you haven't been sent direct.
Some pilots from various airlines,not just the locos, make it a standard call when first checking in,which can be very frustrating when the frequency is already congested.
If the direct routeing that you get involves cutting a significant corner then co-ordination may have to take place with other sectors or units that otherwise would not have details on your flight,this can take a fair bit of time and effort to organise. No problem in the middle of the night when the European centres are quieter and can organise direct routeings between themselves,difficult during the day with much more traffic,military activity,danger area activation etc. Also, when the traffic is busy, it is better for controllers on busy sectors to keep things standard and simple. It greatly reduces inter sector co-ordination which allows us to concentrate more on shifting the traffic safely.
Use a bit of common sense,if the controller sounds busy then don't use the frequency unless you have to. If the frequency is quiet then by all means ask for a direct route, but don't hassle the controller if the request is refused.
Read Dan Dare's post as well. It's amusing but pretty close to the truth!
