Does blocking volumes takes disk space?

Does blocking volumes takes disk space (ex. 2KB or smth)?

I have just tested this by monitoring the size on disk of a map as I added, saved, removed, and resaved a number of blocking volumes. It does appear that they take a few KB.

I am using blocking volumes in order not to move through objects (am I right ?) like stones and etc. So since they are “geometrical” like cube and etc., if I use like 2-3 to fill the shape, it won’t make the program that heavy ?