what about liquids used to build things with, they will be lost too? (Not a problem for me, just wondering if they are discarded...)

Ar right, fluids are discarded. (Just added into information panel.)
The reason is the inventory does not support existence of fluid. And I do not want to give the barrels, since I want to prevent people getting free steel from those recipes (at least not by this mod).

Makes sense; however, I had to ask.

You're welcomed. Free feel to raise questions if you have any.