Yeah, CS is dead wrong. Center a Fireball in a square adjacent to you, and you bet you're going to get a bit crispy.
What does that have to do with yourself as the target? You aren't attacking yourself. You are attacking the square adjacent.
CS said: "the power must target 'creatures' or 'you' and have the keyword Personal".
Mand said: Yeah, no, fireball targets creatures, and doesn't have the keyword personal, and you can fry yourself NO PROBLEM.
If a player wants to attck himself, I would probably allow it. But I seem to remember something about a player unable to trigger his own reactions.
Attacking yourself is 100% legal. Triggering your own reactions is 100% legal, too, it's just hard to do. Since you can't take Immediate or Opportunity actions on your own turn, you have to get creative if you want to trigger those.