In my opinion anyone who is complaining about speed of play on anyone else needs to spend time in a combat zone, that will really make a person appreciative for the time they do have on a golf course, whether it be 3 or 5 hours. Likewise, how about just coming up on someone and asking in a nice civil manner. "hey, mind if I play through"
I went out golfing two days ago and came up on an older couple for a few holes until 17th hole where they were both still waiting on the tee box, mind you the next group was about 300 plus yards out on a par 5. They asked us if we'd like to join them for the last two holes, we figured why not. Anyways this lady couldn't hit the ball more than 50-75 yards, and the guy wasn't much better.
Whats funny was she was saying things the whole time to me about my friend (who has literally not played golf in 10 years, and when he did, it was for a couple months) about her being a Marshall and how she appreciated us playing from the forward tees. Or how he shouldn't be hitting a ball from the out of bounds territory (mind you both her and her husband hit balls down there)
Anyways, point being, don't get your panties in a wad, enjoy the time you got, if you don't have the average time to play a around (4.5 hours), no one is forcing you to complete all 18 holes.