Outside of highly regulated environments, technical staff usually have local admin rights. Is it a risk? Yes, although one that can be minimized. Letting people do what they need to do with minimal interference is an important part of keeping employees happy.
Even if they're not supposed to, most people do, or at least they know an admin login. All it takes is one frustrated person who knows someone higher up and the login is on a sticky note in a drawer. Technical security measures are not and will never be a substitute for proper training.
