You have to be joking?!? Paste the private key of your BTC stash into some internet site web form? This is insanity if you ask me.
Well, if you have a better answer to his question, please share. Otherwise you are just a whining nay sayer.
He had a legitimate concern that was addressed by subsequent posters. The part that was missing, and that should be bolded, is that you create a new wallet and move your coins over before sharing your private key(s). This way you do not risk any BTC.
You are absolutely right. But that was not the question.
If he was worried about other peoples safety, he could have worded that in a much more pleasant manner.