I had heard of similar stories of booby traps and armed migrant farm workers maintaining those fields. They go all the way from fish hooks hanging from trees and the shotguns. And it is pretty much impossible to see, unless you're really looking for them.
I would probably refrain from hacking the crop down myself. You don't know who will come up on you, the grower or law enforcement. Either way, you'll have a lot of explaining to do. I'm a police officer by trade and after this experience I'll always be armed. Before this, I left my semi-auto at home in the interest of saving weight.
It's unfortunate that we as hikers, geocachers, and other parkgoers in general have to put up with this type of thing. It was unheard of when I was growing up. You go to national parks to get away from these types of things. It seems like the criminals are now flocking to these places because of the lack of law enforcement.
The crux is that everyone wants to have law enforcement and feel safe. But not a lot of people are willing to pay for it. It seems like the government, from federal to local would rather put up with what they deem as acceptable statistical crime data than try to put the appropriate number of rangers, officers, etc in the field.
I didn't know who to pass the information on to. I questioned who's jurisdiction it would fall under. I ended up emailing the forest service who put me in touch with a special agent in Washington DC. She in turn put me in touch with the local sheriff's department who handled it.