It's basically an anti-free market policy that some manufacturers leverage onto retailers to keep the price of something artificially inflated because it cannot be effected by market conditions (i.e. supply/demand), instead its a price that the manufacturer says the retailer cannot list it for any less. Something is worth what people are willing to pay for it; not what you tell me its worth. I think in Trijicon's case it also has something to do with military contract pricing, which is a whole other shitshow of retardation onto itself.
But MAP translates into manipulated price fixing and needs to die a horrible death in a fiery auto crash.