A few years back (can't remember the race} we were against a stiff SE on a rolling course (from Wellington to Klapmuts direction), and obviously the guys was starting to spread all over the road to get some shelter, but the Thinkbike Marshal (AZ was on his colours, I think) was having none of it. As soon as someone went over the white line, AZ pulled up next to him, and he was shown in no uncertain terms to get back in line and got shown a "1st warning finger". Should the same person transgress again, AZ pulled up next to him and showed/told him to fall to the back of the group. Third transgression, he got pulled over immediately and told to remove his race number and hand it over. It only happened a few times, and the rest of the group behaved themselves impeccably after that. All it needed was a short beep from AZ on his Hyabusa's horn, and order was restored. The roads was quite busy with vehicles racing to get to their destinations, but our group was controlled well and kept in check..
Admittedly this was in one of the alphabet groups (B or C if I recall) and not the racing groups.