I've noticed the increase in availability for secure phones (as in, there were zero before and now there is one), but even working in information security, I've never heard of anyone outside of Ars Technica or the like actually buying one, let alone using it. I wouldn't really call that a sharp increase in popularity except, of course, the sharp increase of going from zero to one.
Most drug dealers or johns I see just buy a prepaid phone from Walgreens, i.e. a booty phone. Tracfone doesn't verify whatever you activate with, you can just make up whatever name/address.
That's not really a secure phone or black phone, that's just a prepaid phone. Nothing inherently secure about it other than it's difficult to trace. The parent was talking about purposefully secured phones with encrypted phone call and messaging, etc.
