Farmers with .50’s

Looks like a nice time to be a Filipino farmer: a police raid on underground insurgents claiming to be farmers turned up — among other things — two .50 caliber machineguns, an M1 Garand rifle, and three 12-gauge shotguns; weapons which even Filipino communist rebels and Muslim extremists would have trouble getting their hands on. I wonder if this could be related to that US air transport which was fired on by anonymous attackers over Northern Luzon a few months ago.