I've owned Apple notebooks since 2002 as well as a wide variety of desktop systems (both Apple and Wintel -- including desktops I owned long before the notebooks) as well as handheld devices and I don't recall ever getting an electrical shock plugging a system in the numerous places I've lived and visited: various office buildings I've worked, and the countless coffee shops, airport lounges, hotel rooms, conference facilities, convention centers, libraries, friends' houses, B&Bs, etc.
This includes two-prong ungrounded wall warts as well as three-prong grounded cords and power supplies.
The sensible course of action would be to verify that your building's wiring is correct with a simple GFCI tester like this one:
Safety is the number one priority on any job site. Sperry Instrument's testing equipment can be put to good use ensuring that electrical equipment is properly installed and safe to operate. The condition of electrical installations can be established when contractors use test equipment. Any test ...
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You should have one anyhow in general (not just for your new computer) for safety reasons. The building's wiring could be faulty or just certain outlets. Verifying the state of the electrical connection at each point is the sane approach.