Guerilla fishing?

We live accross some woodlands, where there are a few little lakes, most of them no bigger than a pond. So at the end of the afternoon on weekdays and at weekends, we see a lot of people going there, usually for some walk or other. We do that too sometimes. But see a lot of men dressed in army fatigue or cammo clothes, carrying bags, often long ones. At first I was wondering if they were crossing to go play paint-ball or even hunt and I thought it was really weird. But no, it turns out that they go fishing in the woods. I find the whole thing a bit little strange. Firstly because these lakes there surely have very few fish, if any. I wonder if they'd have any less chance of catching anything in a barrel full of rain water. I have never seen anyone coming back with a catch in any case. Secondly because of the whole attire. They really look like some soldiers going into ennemy territory, ready for a long guerilla in the jungle. They often have some really grim expression on their face too. Maybe there is a war going on in the woods and we don't know about it.