You’d be surprised how insecure some of these facilities are, especially to someone who has working knowledge of what a PLC (or other process controllers) does and how it works. You can easily look like a tech who belongs there either troubleshooting something or working on a project.

I’ve been doing industrial controls for 15 years and surprisingly infrastructure is some of the most poorly funded. I believe a lot of these places are run by operating companies, so it’s bidded out (we all know how bids work I think). I’m not surprised when I walk into these places and see the computers are running EOL operating systems and the networking is essentially flat.