Dartmoor in the sun! Addendum

In my last post, I mentioned that we were puzzled by these objects just off our path. Intrigued, I e-mailed those that should know. And they did. Here's their reply. Sorted!

From: Princetown Visitor Centre [mailto:princetown@dartmoor.gov.uk] Sent: 17 May 2014 10:22 To: 'Derrick Parsons' Subject: RE: Spotted on a walk yesterday
Derrick,
This is a ‘control flag’ for an orienteering course put out for an organised event by a local group. It is usually associated with a stamp with pins on so that a route card can be suitably marked to prove the objective has been reached.
Regards
Neil Handley
Information Adviser
Dartmoor National Park Authority
National Park Visitor Centre, Princetown
Princetown
Devon PL20 6QF