I was an elder for over two decades in several congregations with “friends” in many more. This question came up from time-to-time.
The subject(s) of a “marking talk” would NEVER be told about it before or after. If they were bold enough to ask if it was about them, the usual answer would be something like, “Why do you ask? Did it seem to be about you?”
And yet the talk had to be specific enough so that—without actually naming names—everyone in the congregation would know exactly who it was about and why without leaving any doubts.
It’s such a humiliating and manipulative way to publicly shame a person leaving them with absolutely no dignity or chance to defend themselves or correct any false accusations.