Say what you will about “Showgirls,” at least that unjustly maligned film acknowledged that Las Vegas has a seedy underbelly. You'd never know that from “Think Like a Man Too,” which opens by describing Sin City as “Disneyland for adults” before devoting most of its running time to loving shots of blackjack tables at Planet Hollywood, glitzy villas and cabanas at Caesars (the $40,000-a-night “Constantine Suite” alone gets name-checked about two dozen times), and the fountains at the Bellagio. See video: Kevin Hart Leads Battle of the Sexes Th