I bet some of them out there do that, but so far mine haven’t. My spammers usually threaten to kill me, then hang up, then I never hear from them again. If they were using me to slow down competitors, I’d expect more call volume than I get.

How would that work?

    Spammer: Hello?  
    Trickster: Yes hello?  
    Spammer -> *redirects to another list member*  
    Member: Hello?  
    Trickster: Yes, hello?  
    Member: Hello? How can I help?  
    Trickster: You called me?  
    Member: No? You called me?  
    Trickster: No no, you called me?  
    Member: No no no, you called me?  
    [etc ad infinitum]

When this happened to me, the spammer remained on the line and attempted their spiel to the other person, giving me the opportunity to intervene to some extent.

Why do they let you stay on the line? It seems detrimental to them successfully scamming the new person they called.

I think their metrics are tracked and thus they want to avoid short calls or hanging up on someone who calls in.

Yeah this has happened to me. I wrote a simple script that spams spammers from a pool of phone numbers I rent. At one point my calls were starting to get connected to other targets of the spammers. When I noticed this I actually got on the phone and tried to tell the other person that they were being scammed and they seemed appreciative.