The bad part about sitting on the bike when you push it off the center stand is when you get it part way off the stand and you loose your footing or a foot slips and it doesn't go off the stand. Instead, the bike falls back onto the stand and bangs the stops. Doing this a few times not only damages the stops but it will also bend the stand. For those of you who push the bike off the center stand while sitting on it and say "Oh it never falls back on the stand!" you are only fooling yourself.
Another thing to watch out for or to add to your maintenance list, is keeping the center stand bolts tight. Each time you pull the bike up onto it's center stand, the stand pivots try to tighten the left mounting bolt while trying to loosen the right one. I find the right center stand mounting bolt loose on almost every bike I work on.