The couple of times I've gotten the flu, yes. Maybe not down to the exact person, but I know where I was/what I did to (most likely) be exposed.
As far as this virus is concerned, it's been 10 months of hysteria. Like it or not, it's an expectation at this point that you tell people you've been in contact with if you've tested positive. That's where the buck stops for me, though. I never thought it was necessary to tell people that I ~may~ have come in contact with someone who was exposed to someone else who tested positive (that's where my employer was when this all first started).
Now that I know the contact tracing being done by the county is a joke, I'd have no problem shutting that down. What a waste of resources (which, sadly, is not even a surprise or unexpected). Anecdotally, though, I know they do seem to be contacting "close contacts" from school exposures much faster.
Thankfully, none of my contacts panicked. A couple got tested (negative), one was positive (but their kid and spouse had worse symptoms than mine on the same day that I lost taste/smell, so they aren't likely to have gotten it from me), and a couple other people just said "ok, I'll watch out for symptoms".
IMO, no one in my case behaved irrationally. We all just did our best to deal with it and take precautions to not inadvertently spread it any further. I'm very thankful for this, because in the hours leading up to my testing and right after I tested positive, people freaking out was a very real concern of mine.
But, like I said in a previous post, I would do (and have done) the same for another illness.
For me, the importance of sharing that I honestly have no clue where I got it is to break this idea that a mask+6 ft apart is the equivalent of wearing Beskar armor.
It's not. And the idea that anyone can say that a person does or does not need to quarantine or was or was not exposed based on the mask+6 ft rule is absurd and probably doing more harm than good. But that's where we are.
If you're young and healthy, go out, live your life. If you get it, you get it.
If you're old(er), have health problems, and/or are just plain scared, then just stay home. Because a mask and 6 ft may not protect you.
The truth is, if you're going to work, school, or out in public, you might get it. The only way to 100% keep yourself safe and not get it is to stay home and isolate from anyone who isn't isolating with you. MOST people know that's absurd and completely impossible. But a lot of people think they CAN go out, and as long as they wear a mask, it's "safe". Nope, nope, nope. For me, this has become a very black or white situation. Either go on with life and accept the fact that you might get it, or barricade yourself in your house indefinitely. We need to stop pretending there is any "safe" alternative in between.
Whatever option people choose is fine with me. We just need to move past this idea that doing anything more than being sanitary (i.e., washing hands) and giving people personal space (which I'm a big fan of even when contagious illnesses aren't rampant) is keeping people "safe".
And let's stop pretending that some behaviors are "more safe" than others or that certain places are "less safe" than others.