Bravo Sierra. The person who wrote that probably is an expert welder and learned to do specialized operations over a period of years. No novice is going to learn to do that in a weekend or a whole bunch of weekends. Especially shoe-bomber types who would blow themselves up when the acetylene ignited if they could even figure out how to light the match.
The thing that got me was he said they headed south already and the place I bumped into it was on an astronomy group, I wasn't looking for anything terror related. Hot tapping and welding are not to hard to learn. The guy is making threats in his post, could be BS, maybe not.