Since the Hotels & Retreats update I've noticed a dramatic drop in the number of tourists visiting my city. After working through my mods I've pinpointed it to RealTime. With RealTime enabled I'm getting 32 per 10 mins, and disabled I get 600+ (weekly vanilla time units), illustrated by the airport/harbour being barely used with RealTime enabled and full planes and cruise ships with the mod disabled. Before the Hotels & Retreats update tourist numbers appeared normal with RealTime enabled.