Here's my anecdata. It matches my experience trying to hire.
I went to tech meetup last week. about 100 people showed up. The company whose office it was in said before the night's presentation that they had about 30 jobs they were looking to fill and if you wanted one go talk to the guy in the back of the room. During the break before the second presentation they let anyone hiring get up and announce their job offers. There were around 70 jobs available over all. At that point the organizer had the bright idea to ask "who here is actually looking for a job?" Not a single person raised their hands
Two thoughts. "Are you looking for a job?" is probably the wrong way to start the conversation with a good worker who could be lured away for the right price or with a more interesting project.
And I bet not one of the jobs being advertised listed a salary.
Considering it was a tech meetup, was it possible that the people there were there to....meet people, not recruiters? Maybe?
I know I don't generally go to meetups with the express purpose of looking for a job.
Although maybe if someone dropped a juicy high wage job offer for a dream job in my lap, then that's a different story. I doubt that's what was being offered, though. Notice I said job offer, not an invite to go through whatever long and arduous process these companies probably have, only to probably get passed over because I didn't answer one algorithm question just perfectly.
Now if you called it a job fair, or hiring event, or something like that, maybe you'd get a different crowd of people.
I went to tech meetup last week. about 100 people showed up. The company whose office it was in said before the night's presentation that they had about 30 jobs they were looking to fill and if you wanted one go talk to the guy in the back of the room. During the break before the second presentation they let anyone hiring get up and announce their job offers. There were around 70 jobs available over all. At that point the organizer had the bright idea to ask "who here is actually looking for a job?" Not a single person raised their hands