Or they could address the fact that 1 cubic meter of water weights a ton (not hyperbole, I mean a literal TON) and that not even an ogre would be able to launch full barrels approaching that volume around up to meters away as if they were stones, let alone humans and co.
When "sticking to a degree of realism and common sense" and "fixing a potential exploit" can be solved in one shot. A proper matter of killing two birds with a stone.
There is a bit of abstraction when it comes to moving mechanics in video games, to be fair. You're not literally telekinetically hurling the barrel around with your mind. But a party of four people could probably find a way to move a barrel from point A to point B if they wanted to.
That said yah, at the very least the barrels shouldn't be able to be carried in your inventory. They should be way beyond your carry capacity.
