Sabrina loves the little park near our house, and this tunnel leads to her favorite slide, which she loves to be pushed down so she can get a little more speed out of the deal. I haven't found her limits very often, I think I scared her pretty good once going too fast in the stroller (I've rarely felt like such a jerk, although apparently it wasn't too traumatic) but that's pretty much it. She cries when she falls or when strange people try to touch her, but that's it.
As much as I want to leave her alone while she's trying to do physical things, I have to admit I love being part of her adventure. As a former daredevil, I have a decent sense of when she's really in trouble and when it just looks dangerous, and I try to help her avoid disastrous consequences without denying her the chance to fail, because some lessons must be reinforced by pain to be truly learned. By which I mean I only catch her when it's going to be a bad fall, with blood and head injuries.
More park fun in a moment.