How do we trust and regulate at the same time?

My position often pits me against others in the district in terms of policy. I fight for policy that treats teachers as the professionals they are, or at least ought to be, but I'm always fighting against several others who say something like, "But if we do x, then some people will y". They have a great point. There are certainly those who will abuse any right or privilege they are given. There are others, though, who are trying to forge a path into 21st Century teaching and learning, only to find roadblocks at every turn in place because of their less than professional colleagues.

My usual answer to this argument is that it is a management issue. Teachers who violate policy, whatever the policy is, need to be documented and shown the door if their actions continue to be a detriment to students (I am assuming here that the policies are in place to benefit students in the first place). Today I had a conversation with a librarian whose husband is a principal, and it got me to thinking differently. Her point, and again I have to concur, is that the administrators are not available to "police" their buildings, whether they want to or not. They are often at meetings in another location, or tied down with administrative duties that restrict them from documenting anything going on in classrooms outside of scheduled evaluations. It is a struggle just to complete all of the evaluations, and that is when not everyone is evaluated every year.

So, back to my original question: how in the world can we open things for teachers while getting those who would ruin it out of the classroom?