I also think there are. It is more easy for them, they wont need permit to do so. Easy transactions with those who are illegally selling illegal contrabands. One of the reasons also why there are people who can't be convinced about bitcoin is they have this mentality that bitcoin is being linked to illegal activities.
Some people outside the bitcoin community thinks bitcoin used in illegal activities such as buying drugs and buying weapons by militants. Now it is not a problem related with bitcoin it is the problem belong to criminal minded people. Those who think bitcoin is used in illegal activities you cant convince them. But you can tell them thats not our problem at all. This is the duty of government to trace the people who do such things. It will not negative the image of bitcoin community.
Bitcoin is not as anonymous as people think, somebody can easily track you when you try to cash it out