hi:
this is not directly related to gtd but I have been in this situation many times.

For example, you are in a project, developing it nicely, working many hours on it, knowing its structure, pros, cons etc.

One day you have a meeting with some coworkers/boss and they make a suggestion that you feel would completely ruin the project.

You know it because you have problably spent more time on it than them or because you have more experience, a different/better understanding of the project.

How to deal with people in this type of situations?

It sometimes happens that they could start agreeing and tell you, you are the one who doesnt see it, we are majority so they vote and the project gets screwed.

A few months later the project gets into development hell, deadlines are not meet, all because of this simple mistake you pointed out. But nobody will listen if you tell them, i said this was going to happen.

Any similar experiences?

Any tips on how to save projects in this type of situation?