The answer is no. Children are never "drown-proof." 

To ensure your child's safety around water, you must have multiple layers of protection in place to prevent them from getting into trouble, like well-maintained pool fencing and supervision, and you should know CPR.

And even though back floating is an essential skill in swimming, it should not be forced on children who aren't ready for it.

Once infants learn to sit up, they no longer want to be on their backs anymore, so we need to motivate them to want to learn this skill.

I find that distracting them with toys and songs does the trick. For example, my infant students love Twinkle Twinkle Little Star.

How do you motivate your students or children to back float?

I look forward to your answers.