Ask HN: Fake LP vs. LP with subscribe form

I have seen, and read a lot about having a landing page with subscribe form, driving some traffic to it (i.e. Google Ads), and using that to validate the idea.

The way I see this, a lot of people would drop out, because they realise that this is actually waste of their current time, and maybe going to the next search result is far better then filling in the form and then waiting for something to maybe arrive.

A lot better way, in my opinion, is to make a fake landing page, with a "buy" button - making people think that there is a product and they can buy it. If the idea and price is good, then measure the clicks on the "buy" button, and you got yourself a good estimate of where this can go, and how much can it make. Although, one big minus that I see about this - tricking people, that they found a solution, and then actually asking them to wait, plus usually somewhere there is your name on the page too, so not very good PR.

I am sure somebody here had experience with these things, could you please share it with the rest of us? :)

Big Thanks!