I've been using aikido and kali for the last 10 years. Though I'm not very good at these arts, just a couple of moves have helped me keep from getting hurt or getting sued.
The wrist lock from aikido and the knee drop from kali are moves that inflict no harm unless opposed, and look very benign on CCTV and video. You don't want to be using a striking art if you may wind up in front of a jury, though it IS effective.
I've also studied the SCARS system, but that is a completely different mindset from executive protection and casino security. For pure self-defense, that is what I would use, as it opposes and turns attacks upon the attacker, rather than neutralizes them.
It is rather difficult to practice SCARS full out, as you can damage or kill your sparring partner if you are not relaxed and in complete control of yourself. The dummies they provide for practice are less than optimal, and hang on the wall. The nervous system and joints are the points of attack with this system, but the mindset is the important aspect, and I could not allow myself to fall into a "kill" mode when I was on the job.
I have never used SCARS in real life, but if kali or aikido failed, I would not hesitate to do so.
Semper Fi!
Ken Little