True, but I expect the DM to be fairly evenhanded. State flat out 'There's a limit to OAs you're gonna get on this guy, so don't try to push it.'
Then the DM rarely has to worry about such issues, and doesn't have to introduce a bunch of house rules that really only handle corner cases if the group practices the proper amount of restraint that rpgs often require in their social contracts.
We completely agree. When the DM wants to give the character a big, fun win the ogre charges through the party provoking OAs right and left. But not always. It helps if the DM describes the monsters actions in an exciting, plausible way, but the DM should make it clear that he or she will not allow cheez-ball tactics.
Or, to put it another way, the DM and the players should trust each other enough that that the DM is free the run his monsters in the most appropriate way to serve the overall game.
Edit:
I was running a Dungeon adventure. It was a really good adventure with lots of RP opportunities (especially if you added stuff here and there) but the ending was a bit lacking. Long story short, they were looking for a nobleman who was, unknown the them, a demon. The nobleman appeared in the end fight and was intended to be one of the combatants. He had a power where he kissed the player and gained some sort of mechanical advantage. (They took damage instead of him, or couldn't attack him, or something.) Essentially, it was trying to evoke a charm-like effect. First round he rushed forward thanking the characters for saving him, threw his arms around a character and kissed him. I told they player who was hit, straight out, "Here is the exact mechanical effect. But you know the intent is to kind of charm you. So you can play the mechanics straight or you can roleplay the logical consequences." The player defended the nobleman (and the rest of the party played along) and, in the ad-libbed return to the nobleman's castle, actually protected him and trusted him to the point that he escaped. The party really, really hated this long term enemy. Success.
I guess my point is, mutual trust trumps house rules. (And, tangentialy, I often find that too many capricious houserules is an indication of a lack of trust.)