I found this elsewhere.

PLEASE BE AWARE
WHEN ANSWERING
YOUR PHONE!!!
From a friend....
Interesting!
| just got a call from a 304 area code. Thinking it was someone | know in WV, | answered. It was a man claiming to be from customer service (didn't say what company, only "customer service")
The first thing he asked was "Can you hear me?"| remembered something | saw on Facebook saying people are calling and asking if you can hear them, then using the recording of your "Yes" reply as a way to sign you up for all kinds of stuff. So | replied "I hear you" to which he again asked "so you can hear me?"
Me: | hear you
Him: | just need a yes or no
Me: | hear you
Him: *hangs up*
Thanks to whoever posted that story. | probably would have answered Yes the 1st time he asked.

From #OCR interpreted image - errors for free

@paul
Doesn’t seem to be any evidence that this is in fact a scam, nor credible ways how recording someone’s “yes” would be useful to scammers.
What’s more suspicious is your use of | (vertical line) instead of I (capital letter i), now why would that be…maybe to obscure that this is just copy&pasted text spread on other platforms.

https://www.snopes.com/fact-check/can-you-hear-me-scam/

'Can You Hear Me?' Scam Warning

Dozens of news outlets reported on a purported scam wherein fraudsters supposedly falsify charges by randomly calling people and asking 'Can you hear me?'

Snopes
@johannes_lehmann | ran the image, on which I found this text, through OCR and posted the result. That accounts for the |s. | didn't do this on purpose. (Okay, here | do hahaha!)
@johannes_lehmann Here is the original. For your peace of mind.
@johannes_lehmann @paul
But what's the worst that can happen if you only answer "yes"?
https://youtu.be/wfOQsOOyRmw
How To Torture Telemarketers With One Word

YouTube