A recent article from Lifehacker has more on why even one word answers to fraudulent calls put us at risk.
Ultimately, the best practice recommended is to let unrecognized calls go to voicemail. As a lawyer with ethical duties, you need to be diligent about checking voicemail anyway of course.)
These scam calls have a familiar pattern: When you answer the phone, there might be some fumbling around on the other end of the line, and a person might say “I’m having trouble with my headset.” This is followed by a yes/no question like “can you hear me?” Even though this sounds like it’s coming from a real person, often these are robocalls playing pre-recorded messages.
When you say yes, it lets the scammer know that your number is active and that you’re willing to answer calls (not to mention it’s also a pretty good, disarming tactic to keep you on the line). This allows the scammer to then sell your number to other telemarketers for a higher price.
By far, this seems to be the most common form of this fraud, although the FTC and BBB suggest that scammers might also record your “yes” answer so that it can be repurposed later for unauthorized purchases by phone, using other stolen information found through data breaches or via identity theft. Instances of this type of scam are rare, but a general don’t-talk policy is the safest approach, since grifters are starting to use voice-mimicking technology as part of their scams.
Find more on how the scam works in the full article on LIfehacker here.