Trauma- reducing safety warning flag

During our summer (in Australia) a major issue on building sites is the dreaded Plumber’s Crack. It seems to be all over the place and it’s confronting. Exposure to it can ruin your day.
This idea is to issue all site-workers with a strap that clips around the waist. Attached to the strap is a small rubber-shafted flag such that the shaft can be tucked down the centre of the back between skin and work pants.
The flag-shaft is fitted with a springy rubber connection, making it spring out if not pressed into the small of the back by the wearers work pants. Now, anyone on site can see at a distance where to go and not to go to perform their tasks.
If you see a flag sticking up, avoid! In fact, the higher the flag the more traumatic it’ll be for you!