For pushups, I have one word that kills it: Hazing.
A few districts have had incidents within the last five years where a student was hazed, and as a result they fell harsh upon enforcing hazing policies. Pushups and laps that are required for discipline are often viewed upon as hazing, because they can endanger the health of someone if that person is pushed too far. Yeah, I know, ten pushups isn't going to give a permanent injury to someone, nor is running a couple of laps. But when a mom steps in and yells about her baby being treated "harshly", the school and district can't do much more than side with the mom, mainly due to public pressure. I know, it's stupid, but every now and then a kid might have an asthma attack from running laps, and then the directors have a serious situation on their hands. The schools simply can't take the chance. The many who have posted about having pushups and laps, though, I suppose haven't had any incidents recently. Be thankful.