There is some dead code regarding maintaining relationships between institutional patrons and the regular patrons who are members of those institutions.

Specifically:

[1] memberentry.pl, if passed an organisations parameter, attempts to store relationships in an borrowers_to_borrowers table -- which doesn't exist
[2] memberentry.pl tries to build a list of organization patrons (as defined by categorycode = 'I', although other bugs suggest that the intention is that category *type* is 'I') -- but that isn't used.
[3] circ/circulation.pl tries to do the same thing.

Consequently, I propose that this code and references to the memberofinstitution system preference be completely removed, as right now they do nothing.  Furthermore, removing the dead code opens up the field if somebody later wants to do implement patron-to-institution relationships properly.