There is a systematic issue at the heart of the way we do network security.
You can by a lighting / usb cable that can do all of these things and more for $120 if he'd used that he'd never have gotten caught.
We treat network security like physical security at our peril.
I think they are talking about this particular, singular, bad apple and the other companies that bad apple is also attacking right now and stopping that harm as opposed to "sending a message" to other bad apples.
If after the business owner sat down with the perpetrator they decided it is just some script kiddie playing at being a spy then that's up to them.
The wider issue remains that some script kiddie with $120 could have done this and got away with it for ever.
I used to live in an apartment that was within high gain antenna range of the local McDonalds Free WiFi. I had a antenna/wifi adaptor set up in promiscuous mode to listen to all traffic on their network, looking for MAC addresses that connected for a while, then stopped connecting. It'd then switch to that MAC address and BitTorrent until the 500MB daily cap per device ran out, then go back to monitoring mode looking for someone else who'd agreed to the captive portal T&Cs had their MAC address whitelisted and then left. I think I got pretty much all of Game Of Thrones that way...
For a little while, I was monitoring my own home network, and one thing I tried was running map against any reconnection of a known/allowed MAC address, to try and confirm it at least looked like the same device. A RaspberryPi connecting using the MAC address of a phone or a MacBook stood out like a sore thumb. That never turned out useful enough for me to bother wrapping it up into a project I kept running or would have shared.
Probably by actually connecting it to the internet. Since the idea that you can keep people out of your network is probably more dangerous in the long term.
Unless people are manually verifying GPG keys in person all the time, you're gonna need to trust someone. Even with a two man rule you need some degree of trust. Trust is easier when people know they might go to jail if they break it.
Most private and embarrassing stuff rarely ever matters anyways. This isn't a movie