I would say work hand in hand is the best. So far all the events I have covered be it me as an official or others would not get into each other's way. Would always give way to those who are covering the event as well. They would do the same as well.
It's all about balancing. Give and take. As a professional photographer and an official photographer, one should know not to be snobbish or rude to others. Yes it is important to get the one very important image because your client paid you to do it.
First and foremost important thing is why are you being block by others? If you are the official photographer of that particular event you are covering, you should know where to stand and be there early. No one should blame anybody but yourself. If you are really being block, there is nothing to just open your mouth and say "Excuse me, you are blocking my angle. Can you move a little so I have a little space to cover it as well." If that does not work, then just let your client know about it. Do not take things into your own hand.