I, as the PD, can't talk to everybody, but I do talk to some folks. It really depends on the situation. Very often indies are hired just as a matter of course. There is a lot of competition among label promo reps and indies. A lot of times, an indie might call and take credit for an add that they really had very little to do with.
Every station is different.
Every station has different ears, different ideas of what could work, and want to know different pieces of information. Every station has other stations that they look at. If you have five relationships in your first two years, they're your friends. They're going to do you favors because you like to hang with them, go grab a burger and a beer with them. Oh yes, exactly.