Flag running does take skill, for all you novice flag runners out there I will give you guys a helping tip.
When you have the flag, always jump and throw. (you gain more distance vs just running and dropping). Also make sure your weapon clip is not full. Basically meaning you have fired off some bullets from the weapon, what does this do? ; well Reload and flag pickup are the same button, by having the clip not full, the game thinks you are trying to reload the gun and when you run over the flag it picks the flag up instead, cancelling your reload. Rinse and repeat for victory.
What it basically does is, it gives you extra "time" to pick up the flag because you are doing your reload animation; as long as you get close enough to the flag while still doing your reload animation you will pick it up, vs if you had a full clip you have to time your button presses to pick up the flag. Makes it alot easier imo.