http://callofduty.wikia.com/wiki/SitRep :P and only playing mw2

The PRO version of the Sit Rep vs the Ninja PRO (exacly its called Dead Silence not Ninja) is not making the footsteps 4 times louder but it only neutralise its (Dead Silence PRO) effect making them as normal as enemy where not using it, where as when enemy does not have the Dead Silence you hear him twice louder. The part you where correct is that Sit Rep PRO is making your team mates unhearable so there is no distraction from your team mates side and being able to realise that the footsteps you hear is your enemy.

The Pro version makes enemy footsteps four times louder and makes the player and their teammates' footsteps four times quieter, allowing the player to better distinguish enemy movements, and from much further away than normal. This can be particularly useful for Snipers, allowing them to locate targets approaching from all directions and giving enough time to switch to a secondary weapon. The player can also distinguish the surface the enemy player is walking on by sound effect given by the footsteps, giving an even more specific location of an incoming enemy. However, this effect is negated by Ninja Pro, as a Ninja Pro user's footsteps will be at a normal volume.

sitrep has no effect on ninja pro, noob!

The only thing I hate more than cheaters are whiners