There are a lot of things that are great weapons against organized crime, human traffickers, and terrorist groups that are unacceptable as law enforcement techniques. The fact that something is a good weapon against crime is not sufficient justification.
It also needs to be shown that such weapons are not unduly harmful to law-abiding citizens.
Honestly, it's not something I'd thought about much before all the recent government crackdowns on money transmitters. But when I stop to take a look at it, it seems to me that the freedom to exchange money without government interference is close to a fundamental human right.
When I look at it carefully, it seems very very strange that we've accepted that governments have the right to minutely examine what we do with the fruits of our labors.
I get that it's a good tool to stop crime, but so is listening to every phone call. So is recording every move every person makes in public. We're starting to see resistance to movement in those directions, why should our economic actions be subject to the same level of scrutiny?
I'm not ready to throw out the whole shebang, but I've started to think there should be some firm limits.