Here's my thought. For eight bottles of water, you aren't going to need a very large tote bag. So, if you had a tote bag that was smaller and put the water bottles in it, you really would stand the chance of having that tote bag really tossed around. Baggage handlers aren't know for their gentle handling!!!
Now...regarding putting them in checked bags....be very careful. If your bag isn't hard sided, it's easy to get a poke by something sharp. I had a bag with a hole poked in it when I got it at my destination!! Still have no idea how it happened. Anyway....that could allow your water bottles to get poked as well, and that means your stuff is now wet.
For me, that would be a lot of work just to get eight free bottles of water! But, it's up to each person to do what works best for them. I would leave the water at home, pack what I needed in my carry on bag, and not worry about any checked bags. It would be worth the cost of paying for water when I got there.