One of my colleagues had a project where they though it would be a good idea to restrict the amount of cached logons to 1. This would ensure only the last logged on user (the owner) would be able to use the computer off the network. This way the credentials of privileged users such as helpdesk employees wouldn’t be cached.
However when they set the setting to 1 it seemed like even the user itself couldn’t log on any more. Well here is some explanation: http://blogs.technet.com/b/instan/archive/2011/12/06/cached-logons-and-cachedlogonscount.aspx
Basically there’s also other processes filling up slots of the cached logons, and it’s hard to take these into account. So I’d say it was never meant to be set THAT restrictive.