Maybe. But the thing is that they're going after everything. Add some hot key words. Back in the day, we used sigs for our Usenet posts that were loaded with hot keywords.
Anyway, this would cost real money, for sure. But the labor supply for fake friends is huge, especially if you don't care about proficiency in English.
Edit: For example, one could generate numerous fake Russian acquaintances of Edward Snowden, and have each buy a few fake friends. Maybe the fake friends would be impressed ;)
When someone suggests rolling their own crypto a bunch of people pop up to point out the considerable risks.
We need the same for these "wheat / chaff" steganographic noise generation schemes. Steganography is probably secure, but people tend to vastly underestimate the amount of cover material needed.
Considerable money and time has been devoted to "finding the real signal".
The Usenet keyword triggers were trivially easy to filter. Mostly because people just put a list, in all caps, at the end of their post.
We know these are trivially easy to filter because putting a list like [ECHELON CIA NSA GCHQ IRA BOMB inurl:groups.google.com] returns loads. Here's one example, with the handy words "anti echelon block" https://groups.google.com/forum/#!msg/uk.media/KqhWP1rLF9U/G...
