Dyrt Alerts works hard 24/7 to find the campground availability you are searching for, so it's possible an alert will pop in while you are asleep or at other times you can't receive notifications. It is up to you to set your phone or device (not the app) to "do not disturb" during times you don't wish to be disturbed. If you do that, your alerts will still pop in as texts, but it simply won't activate sound on your device. That also means you might miss out on a booking, but again your scan will continue until your arrival date so you may have the chance to book again.