Yes, if you are a "day guest" without a specific Halloween Horror Nights (HHN) ticket, Universal Studios will "kick you out" (escort you to the exit) when the park closes for the transition. Typically, the park closes to regular guests around 5:00 PM or 6:00 PM. At this time, security and staff form a line and sweep through the park to ensure everyone staying has a valid wristband for the event. If you have both a day ticket and an HHN ticket, you can participate in "Stay and Scream." This allows you to wait in designated "holding areas" inside the park while the general public is cleared out. Once the event officially begins (usually around 6:30 PM or 7:00 PM), guests in these holding areas get a head start on the haunted house lines before the crowds at the front gate are let in. Note that Islands of Adventure usually remains open later for regular guests, as HHN typically only takes place in the Studios park.