In the late 90s I worked for a company that was afraid of the Internet. They had one computer in a common area that had access to the Internet but not the company's internal network for the ~50 engineers to use.

The internal network was coax Ethernet. I was working on a networking project at the time and ran a packet sniffer on the internal network and saw that some MAC addresses could access the outside world.

I'm lazy and I didn't like having to go halfway across the building, sit at a slow ass computer to download a datasheet, copy it to a floppy, then walk halfway across the building back to my cube, and finally copy it to my computer. Ain't nobody got time for that.

So I modified my network driver to use one of the macaddrs that had internet access. When I needed something from the Internet, I'd load my modified driver then unload it when I was done. Much easier.

I thought I was doing it for such short periods of time that nobody works ever notice. Of course I was wrong.

After about a month I got called into the IT manager's office. And of course the the macaddr I picked belonged to the VP of engineering who also was the son of the president.

Fortunately they understood that young engineers are dumb and do dumb things and let me off with a warning.