It would be really helpful if the screen could be unlocked using a card that is different from the one used to lock the display, or some other means of locking down the display from unrestricted use. In our case there are many different teachers using the board and we need to keep students from using it. If one teacher locks the display with a card, only that teacher can unlock it with their card, if another teacher wants to unlock the display they must enter the PIN, which students would be able to see.
Another idea could be to implement a feature that locks the display with a usb key (similar to settings lock?)