Ever seen the 'tweet to get' kind of thing, requiring you to post or like before you get an eBook? It's a variant, almost 'shames' you into doing something (social share) b/c you're getting something in return. This is much worse, seen it go so far as exit pages and unsubscribe notices. Manipulating, fear mongering, shaming .. really these aren't tactics, they just tacky. FWIW.