Like others I've seen and used sand bags on various courses.
I've also seen courses hand out green pegs (apparently bio-degradable) that you pin divots to the ground with. I can't comment on there success however.
Atb
I used to see these green pegs somewhat, but not anymore...ever try getting a biodegradable peg into hard ground? Of course, for the big guns, the trend is to provide a mat in winter when grass doesn't grow...no divots, no problem. Pennard did it for a while, but discovered that it only bought three weeks of conditioning on the summer side of the season...not worth 5 months of mats.
Shel
If folks want golfers to do green keeping they must make it as easy as possible to do so. Have you tried slapping a sand bag to your bag? No wonder walkers balk. I hope small tubes with maybe 4-5 tees with sand racks about the course comes into fashion for the winter months, thats not so bad.
I still think the best solution is to push balls to the rough in winter or dry times. I can also see value in providing a mat for those willing to use them. Sometimes they are great because you can generate a ton of spin for short shots
For member courses, its dead easy to assign members to each hole for divot filling etc. Why all clubs don't do this is a mystery to me. Hell, they could even do this for public access courses. Tell players to concentrate on one hole rather than the entire course. Of course, all golfers would still be expected to do their own divots.
Ciao