I ride track and only use Shimano Ultegra SPD-SL's, they are very secure, and with the tension up, are very unlikely to unclip.
If your form is so poor that your feet are liable to kick out sideways enough to disengage the pedal, then I would say work on your form rather than attempt to bolt your self to the pedal.
Assuming a reasonable pedal techique, I think it pretty unlikely you would rip your foot from the pedal.
Some pro track riders do put straps over SPD-SL's etc, but at the end of the day, they are putting it all on a few seconds of all out power, and want to try and cover all possible problems when in competition.