I vaguely remember that this used to be part of the FAQ. However it isn't (anymore). Occasionally people remind askers about accepting answers, especially in the light of poor accept rates. Being able to point them to the FAQ would help.
Few people starting out are able to find the deeply hidden "Accepting answers what's it all about". Considering this is one of the cornerstones of the SO principles, either a link to that post or a one-liner in the FAQ would benefit the community.