Alternatively, the scammer is saving themselves some time; more educated, well-versed people will see the ip and not bother calling in. Less savvy people who don't know the IP address is bogus are likely easier to scam if they call the phone number or reply to the mail.

That's exactly the reaction they want. That aspect of the scam helps filter out people who might be smart enough to properly retaliate if they were to get scammed out of 20k or whatever.