I have the opposite experience. I don’t get any messages from recruiters after having set the appropriate preferences. And I use LinkedIn to connect to relevant people in my field.
(In my case the extra material is relevant... I've run pricing at five companies, which is usually a massively cross-functional job. Unlike my typical competitor, I've also mastered most of the supporting technical, accounting, and commercial disciplines... which makes me a one stop shop for serious pricing problems.)
I get hundreds per year.
Maybe 1 in 50 are decently relevant.
Many are mass spams. A good amount will be in tech I have no interest in, haven't worked in in over a decade, or have never worked in. It's clear the messages are sent without ever actually reading your profile or even job titles.
I wish there were a way to control only the handcrafted / non-spam messages reaching my inbox.
There are seem to be some techniques for verifying existence of an email address without actually emailing it.
https://stackoverflow.com/questions/565504/how-to-check-if-a...
I tried the below services with a custom G Suite domain and, to my surprise, they successfully worked, even for addresses that I know have never been posted publicly (!).
https://email-checker.net/validate
https://clean.email/verifier/how-to-check-if-an-email-is-val...
All the automated messages address me as if Dr was my actual first name, So “hi Dr” or “Dr,…”
So it’s a good filter for all the machine created messages, which is a very very high percentage of them.
For my intent it kinda works the exact way I want it to, but I really only ever login when I'm looking for a job.