All I can say is an absolute no doubt about it YES!! Firsthand experience about 4 years ago or so on the way to a Husker game in Boulder in my friends car. At that time it was a window deal not a bumper sticker. We were going way over the limit and the officer noticed the sticker on the way up to the car as he had it in rear window on drivers side. Cop wrote up a warning ticket and told us to slow down a little. I will always believe it was due to the Fraternal Order of Police sticker.
The donation stickers normally don't work in Florida. The one that works every time is the metal badge that the cops attach to their tag. Another sticker that works is a IAFF-International Association of Firefighters-sticker. I kept my IAFF membership active even after I just recently retired. If a policeman has a medical emergency involving themselves or co workers, they want the firefighter-paramedics to go balls to the wall for them. I will have to admit that this has saved me a couple of tickets over the years even in different states. LT