I had a setup with a remote Asterisk server, and a Tasker app on my phone.
If I pressed a button on the phone, it placed a call to the Asterisk server, which dumped the call into a recorded conference room.
That was simple enough. The fun part happened next. The cops are always shown telling stopped subjects to stop recording and hang up phones. They'll take the phone out of your hand, and attempt to delete recordings. I wanted to address that.
I worked out a script on the Asterisk server where if the phone hung up, it would immediately dial back, and dump the call right back in the recorded conference room. Tasker on the phone would silently answer a call from that number.
That was about as far as I got. I had planned on some way of the asterisk server dialing a contact list and adding them to the conference.