Nudity - no clothes allowed in WDW parks makes for a quick security screen.
All kidding aside, it IS a balancing act. Guest Experience vx. Guest Safety as well a Guest Privacy. WDW does have security aside from the gate security people - including plainclothes security in the parks. I have a number of friends who work in corporate security (not for Disney, in other corporations). Most, if not all, large corporations take security of both their employees and their customers (whatever types of customers they have) very seriously. Many corporations have ex-high level FBI / CIA / NSA people as their cheif of security, and hire many ex-military security personell as staff. I am sure Disney does the same.
-dave