Eggbeaters are not adjustable (to my knowledge) but I keep my SPD-type pedals adjusted to have a pretty firm release tension to reduce the chances of pulling out by accident.

The downside is that a casual flip of the ankle sometimes won't unclip my foot, which can make for an embarassing situation when you don't have another half second to try again. Arriving at school this afternoon (technically yesterday), I unclipped my right foot as I decelerated up to the door and came to a stop, but I leaned left for some reason instead of right, and my left foot didn't come out of the pedal on the first yank, making the second and third desperate yanks as I slowly tipped sideways look pretty funny to the crowd of smokers 50 feet away. crash. It happens.