Of course it would be easy to make it up...but who in their right mind (player wise) would sign that? You play 1 game and tear your ACL, say goodbye to that promise. Especially if Dorion is on the hot seat this season and gets fired by the end of it, Pinto will get another low cap hit contract that wouldn't be worth it.
It's the same premise of, oh it's okay, he will be UFA after this season and we will go after him then. Nope, that boy is gonna get signed more often than not and you will stand there with your di*k in your hand and your wallet isn't on your dresser again. Seen it a thousand times (tommy boy reference anyone? ANYONE?).
Even in your example (although slight condescension given and received), 500k today is more than 250k x2 within the next 3 years (1 year removed after signing a low-ball contract). Your right, they could pay it over the next two years after he signs this one, but as stated above, Dorion's promise isn't going to be the next guys promise if he get's fired and if I am Pinto, it is not my problem that the GM made a massive mistake and signed others to bigger contracts than they are worth (Joseph as an example and try to remember its an example). That's on you.
Pay me for my worth today or trade me, tomorrow is promised to man.