Essentially, force specific layers to only have a certain set and type of tools to be allowed to work on them. So, if you have a sketch layer for example, you might want that layer to only have a blue brush of size 6 px. This would make it harder to render on the same layer, since you would be physically unable to switch to a different colour or brush for that layer.
This would probably require some set up before hand, creating a layer that is forced to only use a specific tool set before you start sketching, however I think it's worth it to reduce the attention needed to ensure you are on the right layer. This is essentially like form validation but for layers.
The motivation behind this is to minimise the chance of unintentionally editing layers or painting layers on top of sketch layers.