Covers or lids for pools with a lock?

I'm thinking about getting one of those $70 special blow up pools from Walmart. It's just big enough for me to soak in the water.

I know in my area, you can't have a pool up unless you got a fence. I also know as long as things such as a hottub have a locked lid, you don't need a fence.

Is there some sort of lockable tarp or lid I can get so I don't need to drain and take down the pool every time I'm done for the day?