This mechanism adds richness to an area of game play many titles simply skip over. While it shares the genre with games like TFC and Tribes, the game plays much more closely to a military flight sim. For those unfamiliar with the way this works in flight sims, your signature correlates roughly to how easily you're spotted by enemy detection methods. Allegiance simplifies this mechanism while keeping the interesting game play elements it introduces intact. Basically, you're ship is given a percentage that determines at what range an enemy can 'see' you.
Allegiance allows players to alter their load outs with an eye on maintaining a low signature.
One can also rotate high signature devices like shields and missiles off an active pylon into your cargo bay, with a corresponding drop in sig. Hiding behind asteroids and avoiding the use of high speed boosters can lower your sig as well. This allows for some extremely interesting game roles to become viable. Hunting enemy miners with a stealth fighter is one of the most satisfying game experiences I've had. Unless the enemy is completely undermanned, you'll have escorts to contend with, as well as the nervous AI piloting the unmanned harvesters bugging out at the slightest sign of trouble.