Telemarketers want to use every trick in the book in order to get potential clients or more likely, potential people to take advantage of, to answer their phone calls. Because of technology, more telemarketers have turned to software that allows the caller ID that shows up on a person's phone to display the same first six digits of that person's phone number, meaning that the first three numbers of the robocall match their area code, and then the next three numbers match their local exchange, leaving but the last four numbers as being unique. This, to the uninitiated, often looks like a call is being place to them that is local, and therefore could be a friend or a business or a medical facility with a legitimate reason to call, and hence gives the aura of legitimacy to what is in actuality, a robocall, made to entice the person on the other end of the phone to answer the phone, so a marketing pitch or its equivalency can therefore be made.
The above is known in the industry as "neighborhood spoofing," which fairly reflects what it is, which is basically a robocall pretending to be somebody from the neighborhood, thereby giving that robocall apparent legitimacy. On the surface, this would appear to be something that shouldn't be legal, because firstly the number as being displayed on the caller ID is not the number that the solicitor is actually calling from, therefore clearly marking this as an act of deception. Secondly, and further to the point, since the first six numbers match the intended target, this means that only the last four numbers of the solicitor caller ID are totally unique, of which there are only 9999 possible combinations of those numbers; signifying that there is a very good chance that at least some of the time the caller ID as listed, actually correlates to a real person or organization, that has that phone number, but has not made that robocall. That would seem to be false impersonation of someone else's identity, and additionally, depending upon what was said or done per that phone call, would suggest that a wholly innocent party could get in trouble with the law, because their number showed up on someone else's phone, in which the number in question that called, has initiated or done something over the phone which has infringe upon that other person's rights.
In point of fact, things are said over the phone all of the time that upset people, even to the point that the person insulted wishes to take retaliatory action, so that, in theory, someone that is very upset, could look at the caller ID, and then through the power of the internet and third party services, be able to retrieve what appears to be the physical address of that person's caller ID; thereupon get into their car and travel a short distance to that person's address since they are in the "neighborhood," and then when confronting that person, verify that the caller ID is accurate by calling that number, and upon hearing the other person's phone ring, come to the very logical conclusion that this is the party that upset them, and therefore this is the party that will pay the price for having done so, even though, that person is actually innocent of making the robocall, of which all of this has happened because the innocent party's phone number, unbeknownst to them, has been hijacked via some sort of software robocall.
Remember that people do all sorts of stupid things, so that robocalls that occasionally use another person or organization's number is exactly the type of stupid thing that will definitely get somebody hurt.