2. How did you keep a strong player from skimming, especially in the days of hand feeding?
How did we do what? That sounds like a good idea! The stories about
how they skimmed might be more interesting. I heard reports of
players dropping quarters into their shoes. One player hit a taxable
straight flush and, before I collected it, "took a break," only to
never be seen again. I had one group of players skim so consistently
that I was convinced there was something wrong with the machines. The
leaders of another team came to the same conclusion, even to the point
of leaving a machine they had played for a week. Essentially, my
approach was to accept it as a cost of doing business.
To partially answer your question, some machines had coin in and coin
out counters. Sometimes they were visible while playing and some
could only be seen when the door was open, but with how frequently
there were other problems with the machines, that wasn't one of them.
I would keep the machine around the clock for a few days and play in
between all shifts, so that I could read these meters after each
person played and compare their actual result with their reported
result. We did a little spying, but I never regarded that as very
reliable. Weighing them in and out or x-raying them to see what they
had swallowed were options that I don't remember implementing.