Having sat through hundreds of safety briefings, usually in uniform, IMHO anyone who continues to read his/ her paper/ book/ computer/ diary etc during this presentation is damn' rude and in all likelihood an ignorant w@nker who needs putting off the aircraft.
Kindly bear in mind that a 'request' from a member of the cabin crew comes with the authority of the Captain and is, therfore, a legally enforceable instruction. Continuing to argue just makes the perp. appear an even biger t1t.
Rant ends.