Actually DMM... Tee's in the course mean that someone behind us has hit into our group more than once per round.
The first time gets a pass... everybody is allowed that one "OMG! I whacked the HELL out of that one!! Wow, I guess I better wait a bit longer today before I hit so I don't hit into the group ahead."
The second time you hit into our group, I'm setting your ball on a tee for you to find it....
The third time, I'm setting it on a tee and then sending it back to you...
If there's a fourth time, not only am i sending it back to you, but we'll have to meet and discuss it in the parking lot....
Usually, people get the hint on step two. The smart ones. Not always.