I am and will forever be confused about something. When I was a kid growing up in East New York in my Modern Orthodox home, where boys and girls talked to each other at any age, Baby carriages were taken out without an Eruv (there were no eruvim), and everyone’s kids played with everyone else’s, I was NEVER permitted to ride my tricycle on Shabbos, or play ball outside. Merely leaning against a car, was considered being oveir on muktzeh.
I live in a frum neighborhood, where ALL the Yeshivish families who live across from me, without exception, on Shabbos allow their younger kids to ride tricycles, scooters, play baseball in the street, and climb into and play on a truck that is often parked in their driveway. I never allowed my own kids to do such things on Shabbos (the playing in the truck would never have been permitted at ANY time), and they look askance when they see Kollel type people doing this. So my question is, what is the actual Halacha about riding these types of toys and playing in a truck on Shabbos. Are they or are they not using things that are muktzeh? At the very least, they are uvdah d’chol, no?