I've seen everything from POP clocks on every tee to printed material in the clubhouse and on scorecards. I don't think the presence or lack of a visible policy does anything to prevent it. My experience is by the time it happens it's tough to pinpoint, just having a gap between groups may not be enough to determine who the culprit is unless there was a steady stream of people leaving the 1st tee at consistent intervals. People tend to straighten up when they see the ranger coming. IMO the problem is not only the people causing the slow play but the ranger's inability to combat it. If for no other reason more often than not they're only putting in their time to earn free golf. In many instances the happy go lucky ranger contributes to it as they make their way around the course making small talk.
I've experienced some really slow days recently and honestly the only thing I can attribute it to is really bad golf and a very busy spring. There were so many people at the course I usually frequent last Sunday there was no way for them to run smoothly. In their defense I can't see any way they could have anticipated it. The starter told me they had 230+ people on the course at the particular time I was there, that included the people waiting on the backed up 1st and 10th tees. That's more than one 4some per hole. They ran out of carts and had groups waiting in front of the clubhouse for carts coming off 18. It was unusual to say the least. As ill equipped as they were to deal with it I don't think the golfers out there knew how to deal with it either. This is a small town course that has one guy on the counter, one cart barn kid and one ranger most days. It just totally overwhelmed them.
It's no excuse for ignorance and really bad golf, which are the usual problems but if what I've seen so far this spring continues I will have to completely change how and when I golf. I predict Colorado is in a for a record year. I'm having to book times for courses I usually walk on.
Fourputt, This will give you an idea how busy last Sun was. Riverdale had no times available on either course and I called before 11AM. I've never seen so many people out. Not even when there were fewer courses here in the post Tiger boom. Hyland Hills is taking reservations for their par 3 courses. It's nuts.