Right. I've seen unconnected grounds. And I still have a 220V dryer grounded via the neutral. Hasn't been code for new installations since 1996, but is grandfathered.

And yes, I know about GFCIs with no ground and the warning. Had one of those once.

Still, an outlet tester will find the common case. I suspect that the situation here is that everything is on 2-wire external power supplies and there is no path to ground anywhere. But by plugging in an external monitor, the user created more external EMI exposure, by bringing his floating ground out of the laptop and monitor. Standalone laptops are tested for EMI compatibility (emissions in the US, emissions and sensitivity in the EU), but that doesn't cover being cabled up to random external devices.

And last I knew you ALSO can put in a GFCI circuit breaker (instead of outlet), swap in normal three prong outlets with ground not connected and use those stickers on the outlets.