> How are smartphones and tablets different from laptops and regular phones in this regard?

Tech aside, one scenario: C level exec parent - or any parent - hands phone or tablet to child in backseat as a pacifier. That's much less likely with reg phone or laptop.

Also, the fact that he didn't specifically mention laptops might simply be an oversight. That is, pretty much everyone will bring their phones or tablets. An exec with a laptop? In a meeting? Probably a rarity.