Haha... that is almost a direct quote I heard from the admissions director at Pacific a few years back.
The only reason a 5th would be necessary is to fulfill a specific requirement: Like sending 4 LORs (3 science proffs, 1 dentist) to AADSAS to knock off the handful of schools that require 3 science, and then sending an additional one, like to Nova who requires a non-science proff LOR.