While this is true, it might be not the most efficient solution resource-wise. Also, from a level designing perspective, lights shouldn’t be placed to fix errors.
In my humble opinion, as I mentioned, you need to reconsider the size of your pieces, and only use modular ones where it is necessary. It is not ideal to build your level entirely using modular pieces.
Here is a link that shows some examples:
http://wiki.polycount.com/wiki/Modular_environments