in regards to the "throttle spring", keep in mind that this advice is focused on the model helicopter community and know that there are those there as well that agree with your position on leaving it in place.
its one of those things that what you want to happen when the throttle servo fails depends alot on what attitude your helicopter is most likely to be in if it fails.
[*]Sport flyers tend to be higher in the air and moving in straight lines. Having the throttle close suddenly usually means you quickly find a spot to auto-rotate to and then you replace the servo[*]Hard 3D pilots tend to be close to the ground and moving in all directions. Having the throttle close suddenly can mean wadding it up into a ball and then you replace a lot of parts on the helicopter[/list]The important thing about the column is that its just advice based on what I have seen work for me over the years. If it helps in some way great! If you don't agree ignore it or express your opinion in the column as well.
Gas helicopters have tended to be a little mysterious as they are niche within a niche. If the information posted helps a few people successfully fly them, I'm happy.