The FCC really couldn't care what you stream, as long as you're not decrypting anything or streaming phone conversations, etc. (stuff that's already illegal to scan anyway).
Right now, as I type this, there are 150 scanner streams listed in the directory at Shoutcast.com, and that's just the ones where the stream owner bothered to change the Genre setting on their Winamp DSP plugin (the thing you need to add to Winamp so it will send to a Shoutcast server).
You can set up a Shoutcast stream but make it non-public, though, so it will never be in the Shoutcast.com directory, as long as you have a static IP or subscribe to dyndns or a similar service...I used to set up a non-public stream years ago when I worked night shift, so I could listen to baseball games inside the office, because AM signals just wouldn't penetrate to our shop...I'm sure Major League Baseball would have had a cow if the stream was made public, especially now since they charge people to listen to play-by-play on their web site...but a scanner feed really isn't on anyone's radar...