i've played for almost 15 years now and i've seen almost every type of player attempt at min maxing. from the one guy who wanted to play a (second edition) Athasian (Darksun) half giant in the forgotten realms as a paladin (who got mad because i would not allow him to jump on a Fireball and absorb all the damage, then killed himself because i told him to read the spell as it detonates on impact), t the one who was unhappy because hi character had 1 stat below ten and thought his character was flawed and useless (he also has 1 12, 2 14's and 2 16's.)
people get this idea in their heads that low stats make a worthles character.
My point is that gamers ( & GM's) sometimes need to roll back the silliness clock, there are some things, such as getting a dragon to hand over some of it's treasure, that should/would never happen. Dragons are, by their nature greedy and covetious, does it make sence to let him give it up, they would most likely fry the entire goup once the suggestion was made. or hand over every poison, cursed item, and baneful items, wait til the party has left the cave than attack them where he can use his most powerful abilities.
DM's control the game, or the players do, either way its up to the person to make the game they want to play, if the characters have abilities, let them use them, but interject a little reality and keep track of monster/npc motivations and you will find that most player hacks into the game won't necessarily work.