hah, no. ABS uses a speed sensor and servos to avoid lockup. in the absence of those things, disc brakes (on a car, motorcycle or bicycle) will definitely lock up if you mash hard enough.
it's easy to lock up the rear because it unweights under braking. the front can't skid on pavement, you'll endo (or stoppie) first. all bets are off when in the gravel.. it's best to use a combination of braking and this is where modulation is key.