Do you have a glance in to see if you can see anyone? Not rudely obviously! Just a glance to see if they didn't hear you knock.
I've found 10/10 can't help themselves, and well, guess where our window is? Yup. Right next to the door
(Very dirty window)
(And excuse the Random bit of lint on camera)
Frosted Glass... Lets in the light, keeps out the peepers.