Most all non-experts sweep a lot. No big deal. Just forces you to try and play against them/use them better.
Now you can learn a foostie classic from the old SF2 days. In those games, you got REALLY fat (hitbox-wise) if you were crouching, so to bait these low moves you would stand up just at the tip of the range where it would connect if you were ducking to make them whiff. Real intimidating stuff for a learning SFer, to not block low in trying to combat the fury of sweeps haha. [/nostalgia]
ahem My point is, sweeps are one of the best moves to learn how to whiff punish. If you can sniff out a sweep, hang at just the right range to make it whiff. Or walk in/out of the range to draw it out. Then sweep it back when it whiffs. It really tests your reactions when learning. (you could also super or whatever, blah)
One of the most satisfying things I learned when playing ST was sweeping a sweep. :wgrin:
Dunno if the hitbox width thing changes in 3S. Also, Necro s.MK easily punishes a blocked sweep.