With Cyberattacks on the National Infrastructure increasing, there are being received by many U.S. citizens "unknown caller" calls from outside the United States. These "calls" are asking for access to PC's within the household. Many people who are not techno-savy believe the ruse that "we're returning a call for computer support and we need access to your PC to ".
This is a known issue on the FTC site, which also happens to technically violate the "Do Not Call" list (since many do not initiate the calls). A call to my own landline provider security had it mentioned they get dozens of calls a day like this, which cannot be traced via Caller ID or *57 (call trace). Requiring the telephone companies to block all non caller-id calls can help in this issue.