MCX, blocked apps workaround

My "too-smart-for-their-own-good" students have found yet another method to run apps which are blocked by MCX settings. Any brilliant ideas how to stop this, besides taking away access to Keyboard & Mouse pane? Blocked apps will launch flawlessly if the user merely sets their right button to open the blocked app. [b]What doesn't work:[/b] 1. Deleting Dashboard from the Apps folder does not keep them from running Dashboard with the above right button method. I cannot explain this. Perhaps there is binary somewhere that needs to be deleted? 2. Custom Dashboard and AppleHIDMouse plists in the Details tab of Group Preferences. For instance, a Dashboard plist Key "mcx-disabled", Type boolean, with Value=true. Or forcing the right button to a certain value. These prefs are forcibly applied at login, but that doesn't stop the student from changing it for that session. Please, help me outsmart these aspiring Milnicks.