From: Nancy Gish

The answer to your question is really quite
simple, although the concept is hard to define.
The community would decide what is on or off topic.

There are, of course, rules of decorum whereby
what should be kept to an interchange between
members should not go on the list.

The community could give the monitor guidence as to what
he or she might accept, or feel obligated to challenge.
Some lists have an off-list list among an agreed few who
act as a kind of senate for the monitor. If the senate
votes to warn or delist a member, then it happens on the
basis of a vote.

The obvious nutcses, tricksters and trolls could easily
be delisted.

It comes down to a case of whether people would want
to make it work. There are tonnes of ways to throw
roadblocks in its way.