it's way too early to say that, and obviously no one is as perfect as you, so don't expect Wie or anyone else to be. Mistakes happen, what else do you want her to say? It's not like she intentionally didn't sign it, so reason would point out that she has no idea how she forgot to sign it.
I'm not saying Wie will be a dominant force in the LPGA nor that she is a bright golfer. But she knows she's supposed to sign it and didn't. She forgot, she thought she had, etc. Her excuse is the truth, if you even want to call that an excuse. If it's not good enough for you, get off your high horse.