No one wishes a price increase because of criminal activities but if people want to carry out criminal activities, they will find a way. Personally, I think they would switch to government cash as it remains the best invisible value swap token. For larger amounts, simply own a bank. For the rest, perhaps the ultra private coins like Monero and Sumokoin have an advantage right now. But as large criminal, you only use what is generally accepted and 100% safe. So I do not expect anything material in this point for cryptocurrencies until after 5-10 years when the tech has matured, proofed safe and is becoming generally accepted (=dispersed further with better price stability).

Please be assured that I do not have any criminal activities planned myself