We noticed small pink plastic bags tied at intervals along a local lane. Eagled eyed me then noticed that each one was above a lump of rouble that had been tipped under the hedge. It was for the council as a marker for where to pick the rubble etc up!!
Good idea, but not in this case, it's a privately owned forest managed by the Forestry Commission, with no public vehicular access - and no dumped rubbish. I wondered if it was perhaps a Treasure Hunt or something like that, as there were several along one stretch of track.
Could be one of this orientating things - I have seen things like this before as markers.