Not really relevant here, Mark is an electronics engineer & he performs all of his testing of modified rigs on an appropriate dummy load. I have never seen any illegal acts performed by him, nor have I really ever heard him even say the word "amplifier".
This project may become open source, what people do with the schematic & knowledge is up to them, knowledge & schematics are not inherently illegal (yet, nor is it intent) so Mark is in the clear.
Mark may be a licensed radio amateur, designing this board to (easily) convert C.B. radios for use on 10/12 meters, this a great project IMHO (as long as 11 meters operation is locked out). (Next in my mind would be an FM mode addition)
Now if you are talking about @ 9:55 (In the video), I don't think Mark would go on a YouTube hunt and start sending links to the FCC because somebody got super jealous and left a note + dead squirrel on his porch (traumatic to a wife & child, if you ask me). I would not imply something like that on an open forum, it's no better than the fool who threatens people because of radio mods being publicly released.
Somewhere someone crossed the line, I don't think this is related to Tech Nine Technologies though.