Outside the US and India, it's not very common to see bumper stickers at all. It's not illegal but it ruins the car and makes the driver look mentally ill.
Oh boy, we’re full blown retarded then lol we have a Tacoma we go adventure with and every new state, park, or city we visit we get a local sticker and throw it on the rear window. Then we have a collage of all the places we’ve gone.
I don’t, just use mirrors like when I drive truck. Also the bed usually has a lot of stuff in it anyways and the tool box blocks a quarter of the window, then my guns mounted up top so the window wasn’t very useful to begin with. It has a backup camera too but I don’t like to rely on that.