Things like this are why I haven't bought HL2 yet.... and it's killing me!
I like the idea of controlling cheating online, but offline - stay away. I think how it's been done with the original HL or UT2KX where you can be banned based on CD/WON/<X> key from servers, but it's still yours to use as you want, is my preferred method.
At face value, I love the idea of being able to dl a game... but I'm afraid that the heart is rotten and gives the publisher too much control over what they want me to buy.
When I go into a store, I want to buy the game. Steam appears to be more like an extended rental at the moment.
I almost expect there to be at "Insert Coin to Continue" the when you die in HL3. (Fully linked to the credit card on your steam account, of course.
Perhaps things will get worked out in the future, but for now I stay on the sidelines and try not to be bitter at Valve.
"I trust in my abilites,
but I want more then they offer"