Horse trail vandals

I was interested to read on White Horse Pilgrim recently about his displeasure at endurance riders marking the bridleway, because similar markings have appeared on the Wenallt trail.  I do not know whether this is from a fun ride or an endurance ride.  It definitely was NOT from the Briwnant fun ride.  The markers occur all along the horse trail so I am pretty sure they are related to horseriders.

These markers are sprayed on with bright orange fluorescent paint.  They are ugly and deface the trail.  This is horse trail vandalism.  These marks will not wash away and may be there for years.  They are not even necessary as the trail is pretty clearly marked anyway.

I hate this.  If you are a local reader and know which organisation or group did this, please ask them to stop.