Something makes me think they are monitored as thoroughly as a military compound though, so it'd be tough to do, but a worthy challenge.
You tickled a neuron connected to a memory... sorry.
So, over the years I've seen many warrior's collections of military historical objects. Many warriors collect old stuff. Hell, I've got a few bits still that have not been washed away by life.
We've generated quite a bit of it on our soil... generally during the civil war or the rev war... but most historical bits tend to come from the more recent one of course.
Generally, civil war battle fields tend to be protected national parks. Some are very protected. Gettysburg, of course, is very protected with roaming guards and some fancy systems.
Of course, warriors tend to have some skills and knowledge in their toolbelt. They might be able to dodge those guards and dodge the security measures.
I worked with a fairly senior officer for a few years on the civ side. In his office, he had several containers of various miniballs, belt buckles, and other such metalic left on the fields of battle at Gettysburg.
He tells fun stories of sneaking in wearing gilly suits and evading all the hurdles in place.
Apparently this is seen as a bit of a personal challenge and he knew of others that had done the same dance.
Sure.... stealing our history a bit... but I sure enjoyed viewing his collection.