It isn't just a slogan:
Loud pipes save lives. (You can lug it a little where you need to be quiet, or downshift and wake people up.)
My neighbors have repeatedly told me that on the infrequent occasions I do wake them up, they just turn over and go right back to sleep.
They don't mind my bike at all--at I have aftermarket pipes with no baffles. I can be quite loud when I want to be.