We would like the ability to lock templates so that users cant mess up prebuilt templates.
Currently we allow for locking of certain properties in a template. I usually recommend just locking the QTY property or QTY Formula so it's harder for them to mess around with the main calculation. I don't recommend locking the properties used for variables because then they can't change them. Another best practice I tell clients is to just use the "export template tab" button to make a back up or a copy of templates so if something does happen to get altered or changed to the point of no return, there is a way to revert back to the original, completed set.
Thanks for the feedback, I'll submit a feature request to dev on your behalf.
Look into the Advanced Property of the tool or part there is an icon on the right that looks like a lock clicking on it changes it form unlocked to locked you can also click on the light bulb and it will turn off from normal view then looking at Hidden items you can lock the property and they wont even see them in the advanced property view, if you leave the check box checked they will still show up in the input and Report view but as Kieran says they are not editable until changed back in the Advanced Property view.
Now if you need to add confusion so as to hide things further you can place information in parent items and have the child items inherit it and or rout the information through multiple properties so it becomes difficult to track down. look through the formula posts and study the [[..]] function.
It will take some time to get use to the Advance Property screen, as I look at it I don't see numbers and text all I see are redheads and blonds... a little Matrix for you.