Companies like bigspy are able to find the Post ID from an Ad ID without having the access token.
How is that possible?
For example this user hides posts, only the Ad ID is visible:
https://www.facebook...&media_type=all
This is an example how a post looks like, this isn't visible in his profile (hidden post):
https://www.facebook...W14r1wvfJEA1Nml
Will pay for anybody who can find me a way to get public post links for any ad