This can be used for a variety of bad ideas, my friends and I enjoy driving around smoking blunts and listening to people we hate get arrested, feels good man, but it can also be extremely useful just throw one earbud in and know what the pigs is up to at all times
http://www.androidzoom.com/android_applications/entertainment/scanner-radio_gler.html
Comments
first off, a portable scanner is $100, which is automatically cheaper than an android anything. Catch it on sale, or have a friend who works at radioshack, $80 or less.
Secondly, a lot of these scanner streams have a 15 minute delay, making it useless for any "bad ideas".
One advantage to your idea is that in most cases and places, committing a crime with a scanner is another charge in and of itself, while a cellphone is not.
what you COULD do is...
buy a scanner, set it up at home.
Set it up with a phone that can auto answer. (most cellphones can do this)
Take another phone, possibly a disposable one, and call your scanner/phone.
and if anyone catches you, just hang up.
Could work
Seems like a plan, however I would add the Internet aspect to it and make things easier. If the scanner can be connected to a system you can easily operate it via Internet.
It's in legal limbo right now, but you can find it on the web.