Maybe you don't really need hot tub covers especially since you're not likely to leave a hot tub unattended, but maybe you also ought to think again.
Same way that you should reconsider reusing old shampoo and mineral water bottles as containers of potentially harmful substances like dishwashing liquid, ironing aids and solutions for cleaning jewelry and other stuff.
The thing is, we always mean well. And we always assume we're vigilant enough. Sometimes, however, just a ringing phone can distract us enough from our curious kiddos and can result in an emergency hospital visit.
So, those heavy medical or law books should nowhere be on a high shelf where they can fall and seriously harm your child. Trust me, better risk having your kid have fun ripping it apart, than it making a bad landing on your kid's head or chest.