The team at the ISP I used to work for had two machines; a corporate one on the corportate network with all the usual group policy lockdown hassles, and another machine that was on a seperate space they'd carved out of the out of band administrative network for the various switch and routing gear.
You very quickly learned to lock your workstations, lest you find your non-corporate machine's home page set to some adult site, and I'm not talking about 'tame' sites like playboy, but the really raunchy hardcore sites. (this was done with the blessing of the infosec people, who were even worse than we were...)
Then there was 'That Guy' at LAN parties who had their computer that routinely had not-kid friendly wallpapers, screen savers, etc. on it. He also didn't lock his workstation, and also had a habit of running a torrent client 24/7 on it, regardless of the network it was one. THis was back when world of warcraft was a thing in our group, and one day we discovered he had fallen asleep whilst logged in. We didn't do anything bad to his account, but there was a spare keyboard that got plugged in and messages were sent to the guild chat about how large their pants were, and proclaimed their love for murlocs (one of the 'cute' monsters in the game), which he hated.
As revenge for running a torrent client when we told him to stop, we did change his desktop wallpaper, icon set, and sounds to murlocs. That was also the last time he was invited to a LAN party as well.