I think this could be a usefull adition to LW.
I didn't think the idea is very original either, but it is worth the effort building it into LW.
Now with layers you can set a foreground and background layer.
But sometimes setting a backgroundlayer doesn't give you enough feedback to model good enough. But setting the background layer as workable on could be dangerous to that layer.
The option to lock a layer exist in many other apps to ( mainly CAD software) and also exists in LAYOUT. And CA's already know how usefull it is, I do :)
Since Newtek is focusing so much on CA, I have a CA(modeling) example :)
Suppose you have a character with clothes on , the clothes are fairly complex and would be a pain to remodel from 0.
And suddenly the chest of the character needs to be changed, and the clothes need to fit around the new chest. Setting the chest as a Bg isn't the best practice, but also setting it as a active layer could cause errors. But if you would have the option to lock the layer, so that you only effect the points/polys/volume on the clotheslayer, that would make life alot easier, and would speed up production.Because now you can see if the clothes go thru the chest or not, with normal inactive BG you cannot see it as clearly as on normal active Bglayer. But a active BGlayer holds the risk of deforming the mesh in the wrong places.
This is how the lock layers options would look like:
A usefull addition?