It's not a work-around so much as it is how you've always been supposed to use it.

Where is it documented that you need to be proactively cautious when using each() by proceeding it with keys()? Or to make sure you avoid using each() if your hash may be touched by other code inside you loop?

The perlfunc entry tells you there's one iterator, true, but doesn't give you any insight into the potential pitfalls that may lead to. That was the purpose of my post.