Apple designed iOS to wake your locked handset’s display in the wake of incoming notifications, and while this helps to grab your attention, it also tends to grab the attention of others. You can easily prevent this by turning notifications off, but then you run the risk of missing important notifications altogether.
Love it or hate it, Apple’s notification-oriented display-waking feature is probably here to stay; but with a free jailbreak tweak called IllLookLater (iOS 11) by iOS developers N104 and Julio Verne, you can better control what wakes your display and what doesn’t.