Lets say you know a building owner who rents out some space, including
some that is set up for studio use. The landlord does most of his own
electrical work, and definitely anything he knows was self-taught,
probably by zapping himself many times.

One advantage to being self taught is that you develop a good sense of
only doing what is necessary. But this has a down side and this is
the problem behind today's question.

A totally unqualified "electrician" can wire up an outlet very wrong;
out of phase, with hot and neutral reversed and with no ground
connection. But he can plug in his work lamp, or his 20 year old
transistor radio, or any number of cheap consumer products and they
will all work fine.

This "working" outlet can be a real headache to a studio owner. But
the landlord listens to your concerns (while ignoring any word with
two or more syllables) and replies with complete sincerity "But is
work good" and proceeds to plug in his radio (with sawed off ground
plug) and beams with self-pride as his outlet provides the necessary
juice for Neil Diamond to fill the room.

Can anyone offer a simple, straightforward explanation for why this
guy should care that his outlets are wired correctly? How can I
present the facts so that it he will decide its worth fixing? (on his
nickel)