Another Day, Another Grey Hair...

I was cooking my egg whites this morning while Emma played with the cats in the front room.  She was within earshot, and I could hear her jingling the kitty ball, but when I went to check on her she was nowhere to be found, and the noise stopped.  I call her name.  No answer.  I scream her name a few times, because usually she'll cry and then I find her.  Still nothing.  This is when I really started to panic, and continued to yell as I searched the downstairs.  I darn near had a heart attack with all of the scenarios that ran through my head.  I can't help but think about the horror stories that have been making their way through the blogosphere and on twitter lately. 
 
Finally, Emma started to wail and I found her hiding behind the recliner - right by the outlet our lamp plugs into!  I admit this sounds awful, hoping for my daughter's hysterics.  Any noise from her would have been great, but unfortunately she becomes as quiet as a mouse when I call her name.  But when I yell, I get a reaction and find her immediately.  Then I have to spend the next 15 minutes calming her down.

I have two questions.

1. Do all kids do this?
2. When should I start sending her for therapy?