i wrote the company and they responded with the reason.......

I appreciate you writing to check on the stickers you have seen on the Budweiser delivery trucks in your area.

To answer your question, the “Honk – I’ll Pull Over” sticker is a show of courtesy to other drivers. The Budweiser delivery drivers understand that while they are behind the wheel they represent our company - so long as our logo is on the side of the truck. Since quality is something we strive for in every aspect, we believe that this quality and courtesy should be extended to the road.

Bottom line… so long as it would not put others in jeopardy or would break the laws of the road, if you are behind a Budweiser truck that due to the weight of the vehicle and load is moving below the speed limit, if you honk, then the driver will make way for your vehicle.

Does that answer your questions?

now you know