I got a cold call on my cell phone yesterday. Someone was looking for me, trying to sell me something. Typical cost of a call like this (not from a boiler room)--perhaps $100 when you add it all up.
When I explained to the person what I did and where I did it, she realized that I had no interest at all in what she had to sell and politely hung up.
She followed up by email asking for a referral and I asked her why she didn't Google me before calling. Her answer, (ellipses are hers) "It depends... you came recommended by more than one source (confidentially). If I trust someone I make the call right away... if someone is interested in talking, then I dig deeper."
So, it's okay to waste my time (and by extension, hers) and she'll do some research after she's got a warm lead.
Twenty seconds in Google would have saved both of us a lot of time. More important for her, that twenty seconds could have turned a "no" call into a decent shot at a referral.