@yrrsinn I've never seen a barrier to these kind of areas, and there are none around here.
Obviously they don't do live shooting in these bits...
There is a separate area however that does have lockable fences and a red flag, and obviously I don't go in there...
The woods around here are more for 'outdoorsy' training and newer recruits as I gather.
We hear live round shooting around here constantly as we have a ton of ranges, obviously all off limits from the public.
Down in Devon I've seen these signs too and again never any barrier.
But there is also a big big range for tanks etc. which is closed when training is on.
So I guess it depends on where you're at.
I'm not so stupid as to walk into a place where I might get shot! Probalby