Re: Zero enforcement in the UK
Asterisk: Yes you can blacklist which is nearly useless.
On mine I have a message (IVR) that says: "Press 1 if you think we'd like to speak to you, press 2 to leave a message. Unsolicited callers - please hang up."
No spam any more at all. The auto diallers don't know what to do. You can bypass it with a white list for friends and family if you like if they pass CLID (painful!)