Oh, how wrong you are. It's absolutely advantageous for an AM to screw you over. Sharing your profitable campaign data with as many of their affiliates as possible is the easiest way for them to maximize their affiliates' revenue, thus making themselves more money. Other than the original affiliate possibly leaving for a different network in the extremely unlikely event that they found out, where exactly are the disadvantages you speak of?
Speaking as an AM, if people DO talk to me, I always qualify it with a "Are you cool if I talk to other affiliates about some of the stuff we're talking about now?"
If they say no, I keep my trap shut to my other subs about it, but occasionally I get tempted to use some of the stuff myself.
I
try to avoid directly competing with my own subs though, as I mostly run offers that aren't available to them, or aren't even on our network. I like to pretend I have some ethical inclinations after all
Landing pages, I'll help with as much as possible, but I usually tell subs that while it works for me if they tell me their keywords, I'm not actively going to ask as it's kinda the same as a trade secret.
But yeah, chances are, your AM will either use the info themselves on their own campaigns, or if they're not running any, they'll share them with other affiliates.
We make our money when our subs make money. Subs make more money, we make more money.
It's pretty obvious what most people will do to advantage themselves.