Hello Bill
The problem here is is one of definitions; that is, what does "... in the open ..." actually mean.
I used to think it mean "not in cover, i.e. not in field defences". But then I saw one of Pete's replies (don't ask me where!) that indicated it meant "in open terrain, i.e. regardless of whether in field defences or not".
The question has been asked a few times, so I think it's probably worth a FAQ.
Puzzled

(but hopefully no longer in this particular case!)