Derek,
First, the most important safety system for your router table is to make sure that the plug is removed from the power source before making any bit changes or adjustments. This is the simplest and most reliable safety cut out system.
For convenience and additional safety, my router table has an outlet that I picked up from a tool supplier with a paddle type stop switch. You lift the paddle to gain access to the start switch, and if you bump it with your knee the power is secured. It was around $20 8 years ago. The router table is unplugged from the power source when I make changes.