Omigosh Sunnydays, we are having the same kind of days, except my dcg is 15 months old. She spends the last part of park and library visits in the stroller due to non-listening as well. Since your dcg is new it's probably the same problem, even though they are not the same age.
My dcg and yours are just getting their first dose of rules and learning that following them is important. Thankfully, my dcparents are working on their daughter as hard as I am to teach her that she can't dump the toys or the buggy and then climb in or spin on the computer chair or run away outside and so on and so on. I'm beat! I hope you can get across to your dcparents that they have to be stricter at home with rules.