So I'm wondering about those stupid legalese footers on some emails that say something to the effect of "if you weren't the intended recipient, delete this emai

So I'm wondering about those stupid legalese footers on some emails that say something to the effect of "if you weren't the intended recipient, delete this email and pretend you haven't already read it" - would that have helped in this case? Or, if the email had that footer, and Arrington published it, would that open him to legal liability? Or, are those footers just a total waste of space and time? Any lawyers in the house?