I was a timer for 25 years. (Runtime Services, Buffalo, 1981-2006)
One thing I never, ever did was to publish a race number that could be linked to a runner. No. Cannot do that. (Of course I'm not talking about registration lists for the registration workers to use.)
When I published registration lists online I never gave the associated number, and never (anywhere) the actual age. Age group only, and often not even that (because it's not really needed). City and state, yes.
And yet I see this done with online (and printed) results all the time. All you need to do is remember a race number, get online, and you can find out who it is.
Over the years I had many people contact me trying to get runner information (invariably guys looking for information on women) and I never gave it out. Well, there was a law enforcement thing one time when they were looking for a murderer, and of course I had queries and subpoenas from insurance companies from time to time, but otherwise I wouldn't do it.
I really, really disapprove of the runner number field in online results. It serves no purpose and adds zero value to the output.
As for people using false names -- that's not the greatest idea. What if you're injured, maybe not conscious? I might have your address (unless you faked that) and the first responders or the hospital might be able to work from that and figure out who you are, but maybe not.
Sure, that kind of thing is rare. But when I was working, I had some cases where a runner died out on the course (or at the finish line) and the responders came to me for the information.