They shouldn’t allow users to moderate the site, even if it means longer response times to remove spam, since it very commonly leads to the users abusing that power to remove things that they do not like even if they do not break the rules. That happens very often and the moderators are okay with it because allowing users to remove other users’ content so it goes with the “editorial line” of the commenters of the site lowers dissent and therefore they have to work less.

A perfectly secure system is one you can’t use.

Another version is:

The optimal amount of fraud is non-zero.