[Closed] People riding and walking the wrong way at trail centres

In my last couple of rides at Sherwood, I've come across loads of people riding and walking dogs (off the lead, naturally) the wrong way up the Red trail.

Is it beyond the FC to stick up signs on back of the waymarkers saying something along the lines of "One way bike trail, caution advised"? As I see it, it's surely a matter of time before someone comes around a bend too quickly, has ropey brakes / tyres and hits someone or a dog that's bounding about.