EA's Medal of Honor touted itself as a realistic look at modern warfare. Military experts and soldiers consulted on the game to ensure its accuracy. Those in-game ads, though? EA consulted with itself.
In the game, there are tattered fliers for Mirror's Edge and Battlefield: Bad Company. Both titles, of course, are EA games.
The likelihood of a soldier coming across these fliers while on patrol are low, but possible.
Personally, stuff like this doesn't bother me. Easter eggs like this - knowing self-references - are great. Really like when game developers are willing to break the third wall and toss a wink-wink nudge-nudge to the player. Yes, even if that knowing look is an EA advert.