If those allow anonymous payments to be made as cheaply and easily as Bitcoin, then Bitcoin wouldn't be needed. For the same reason the cryptolocker guys are going to increasingly prefer bitcoin to other methods over time, those wanting to receive rewards anonymously for providing crime tips will want to receive bitcoin over other payment methods.
My point is, whatever advantage Bitcoin gives criminals looking to stay anonymous while doing crime, will also apply to crime fighters looking to stay anonymous while they receive financial compensation for reporting crime. It's a double edged sword.
Law enforcement and community policing efforts should be innovative and use Bitcoin's new capabilities to their advantage.
I suggest you visit the scam section:
https://bitcointalk.org/index.php?board=83.0
Cause until now , bitcoin is the something like this
Also , offering rewards for catching criminals will be the first step. It will take 2 seconds for the next one , hiring a hitman or a hitwoman.
It's human nature , no matter how many good things something does we find a way to use it so it fucks us back 10 times over.