Does anyone know if MB will cover the key under warranty? On one of my keys the big lock button has a crack in it. You can see it hasn't been abused it seems like it cracked right by the 'lock' from normal use.
beware though, hold onto that old key. There is a hard limit on the number of keys that can be assigned to per car (i think it's 8) and it'll show up on any records of the car so you need to give it to the next owner, or they might have a negotiation point.
My dealer showed me a printed page that said MB wasn't covering cracks on the key anymore... (the wife's has cracked. mine hasn't YET) Looks like this is becoming a VERY common problem. Sucks I can't get mine replaced.