You have a tough job JO. This is just a reminder that it seems redundant to go over the rules a million times to the same riders, but it has to be drilled in.
this is a yellow flag it means caution, track is closed stay off, no pit racing .............and so on.
Another reason why it's important to enter and exit the track at the designated spot.
Probably isn't a bad idea to put a huge orange flag on the water truck that is visible everywhere. Like 15 foot off the truck. As a last resort to people that mistakenly go out on the track.