I guess it is like each does what he feels comfortable with and that will do the job.

As a contractor who is developing offsite for a particular client, it is possible to not even know the sys admin, or to have the traiing hours in the contract to bring him/her up to speed as to what their function is going to be in the application. As a result, I try to develop with the least amount of admin intervention. I don't intentionally try to leave them out of the loop, but I don't have to go to great lengths to include them either.. I guess I am not really into all the required politics of getting more on board than the end user, which is basically the ones that can make or break your hard work. I try to make their job as easy as possible, which will translate into less man hours to use the application, and thus impress the Bean counters.
I am speaking very generically here, because many times having all on board smooths the passage in getting something entirely new up and running and ahead of the competition.