That does make sense, but I don’t think it’s a good enough reason to die of dehydration. If you wield a can, you can still carry it around unsealed, and if they were sealed prior to being placed in your inventory, then you can still carry them until you drop them.
I know that if I were in that circumstance, I’d find a way to make it work. I had to waste a first aid kit on bite wound because a fat zed on a bush moves faster than my character, while sprinting, right now.
If you make clean water, then you can put it in a can, regardless of whether the can is in your inventory, or just on the ground adjacent, but you need a bottle first.
Edit: Never mind. I just found out that if you wield the can first, you can place water into it.