Certainly open to a more global refactoring of LPPE. In fact, I believe with the ldaptive changes that @seac is working on, some of that will be taken care of and will be noted. 

As for this particular change, we could halt the flow and throw the exception but I believe the desired use case here is such that if an account isn't setup with password policy rules, the flow should resume normally as if the account was setup correctly and all checks passed. This happens for instance, when a new ldap domain is brought into the authentication settings and say, its specifically for admin/staff/etc accounts that may never become a part of the password policy sphere. I realize it's weird, but it does happen :)