Are you sure about that? I signed an address with the Electrum wallet and the receiver verified that signature with a Brainwallet tool. So I thought this was sorted out. Is there something wrong with the way Electrum is doing this, because it is very important to verify the owner of the wallet, before the money is send.
Can this be manipulated?
Yes I am sure.
Nullius confirmed here in an old thread. Check it out.
https://bitcointalksearch.org/topic/m.29647827
I don't think it's wrong or manipulated, just non standard. It's worthless.