My LBS has "Power Grips" straps.
Mounted at an angle across the pedal, you insert your foot and when you straighten your foot it effectively makes the straps tighter.
That seems ok.

I tried two different BMX Straps...gave me good leverage if I jammed my foot forward but not when keeping the balls of my feet on the pedals.

Im finding that with more practice I am able to tighten my straps down and still get in and out of them ok