What is your proposed time limit (when someone has to be hired to fill the position) and "cooldown period" (when hiring can re-open after someone does not meet expectations in practice)?

It's obviously a difficult problem to write rules around, and there are so many ways for companies to weasel out of any rule you write. The general principle is that you should not advertise a job if you don't actually intend to fill it. But you should also not do it if you have some "theoretical job" you can create and are just fishing for candidates. Any rules I write down here will have trivial ways to work around them though.

What does this have to do with the original comment?