I don't think most people will act this way. First of all, keep in mind that the average cRPG server crowd is a bunch of lemmings, they don't even think about what would be the best strategy to win the round, they just want frags.
And even if you think of taking the flag, there will be a decisive fight in any case, so where is the difference between fighting, THEN the winner taking the flag, or waiting until the flag pops up, THEN fighting around the flag and the winner taking it? In any case there will be a fight needed, and most people will prefer to have the fight sooner than later.
That's at least how I imagine it to work...