Telling hacks from a demo

Is there a way to see what addons someone has from a demo file that they made? I have used a hex editor in the past to find hack convars getting set along with other ones that the server sets on the client at the beginning of the demo (see example bellow).

http://puu.sh/qXTS

I’m having trouble with another demo as I can’t find any, even though I’m certain he is using them as he admitted it over Steam. Unfortunately I need more evidence to ban him on the server group I administrate him besides a Steam screenshot.

Any help would be greatly appreciated :).