Award ticket capacity controls are part of the broader yield management game. The idea is not to give award tickets if there's more than X% statistical likelihood that a paying passenger will come along, just as they don't sell cheap tickets if there's more than Y% likelihood that a full-fare passenger will come along.

Since they're dealing with statistical probabilities, making more award seats available means just accepting a slightly higher probability of having to turn a paying passenger away at some later date. Airlines will often do this to keep a high-status elite happy, on the grounds that so doing is worth more in the long run than the statistical expected value of perhaps selling that seat. It's not an "unofficial program." It's just good business.

The way this is done is to call the elite reservation desk and ask them to ask their yield management department if they can free up more award seats on flight XYZ. (Details vary by airline.) If the flight is fairly empty, so it's just a question of increasing the chance of turning away a paying passenger from 2% to 5%, they often will. If it's comparatively full, they won't. Where they draw the line depends on how good a customer the requester is, based in large part on his/her elite level, but other factors (as passed on to the YM desk by the elite desk) can come into play as well.

The worst that can happen is that they'll say "no."