Bank competition/HR/Acceptance Rates?

So I spoke to someone on the buy-side and I've got a question to those of you who are familiar with this:

I was told that HR at most bulge brackets as well as boutiques may not necessarily speak to one another on a daily basis but do speak to each other occasionally and inquire about a candidate to maybe see if they've interviewed with them (this is what I was told so I'd love to hear if this is verified).

Apparently, banks of all sorts/sizes keep track and compare amongst themselves the percentage of offers extended related to those offers being accepted -- and banks do not like to extend offers they think may be rejected.

Thus, if an incredibly strong candidate interviews at a firm HR may be inclined to see if he/she is interviewing anywhere else, and if he/she is, may wait to extend an offer and instead see how this persons other options go based on whether this candidate reaches out to the bank upon getting another offer somewhere else (this also shows demand for the candidate but even more importantly, the candidate wouldn't reach out to a firm letting them know he has an offer unless he/she most likely wants the bank he's reaching out to to extend him one as well so he can accept that over the prior offer [sorry this is a lot here]).

Thus, I've spoken with someone who knows someone in college who was such a strong candidate banks were waiting to see where they ended up before figuring out to even extend the invite to a super day or not and in some instances banks just declined the super day offer because they believed this person would not accept an offer.

Does the above actually happen? Does anything like it actually happen or not?

Sorry for the long post I'm just curious --- thanks!