LAS VEGAS (AP) — As volunteers streamed in to donate blood, doctors tended to the wounded and investigators scoured the scene of the deadliest mass shooting in modern U.S. history, Las Vegas tourism officials moved quickly to protect their valuable franchise in a city where branding is everything. "What happens here, stays here," the official slogan advertising agency R&R Partners developed in 2002, with a wink to naughty behavior, no longer seemed appropriate after the Oct.