I used to work at Babies R Us and they had free monthly magazines just for grandparents, and occassional grandparent seminars, with ALL KINDS of stuff that's changed since they were parents. (Things like back then, you were supposed to put babies on their belly to sleep so they didn't choke, but now we know that cases of SIDS went down dramatically when they changed the rule to putting babies to sleep on their back, etc). I know what your mil was thinking there: it's a nice safe looking place, and the people at the park seem nice, AND THE WORLD WAS DIFFERENT when she was a parent. I know that she was thinking that she'd have to stop your daughter's fun time and possibly encounter a toddler tantrum for taking her away from the park so soon (toddlers don't understand what "just a minute" means). But the fact is, it was dangerous because the world is different. I'd rather they both just stay at the playground and have fun awhile, and when it's snack time or your daughter gets thirsty, THEN they BOTH go to the car for snack and water. I wouldn't get "mean" with grandma, but I would just explain that things are different and let her know you want her to have a relationship with your daughter, but these are the rules. Thankfully, nothing happened. Don't let the fear of what "could have been" ruin relationships, but do lovingly put your foot down. If she can't respect your position, THEN "grandma time" has to be supervised. (I do this with my dad----he blatantly disobeyed my wishes on something, and when I tried to explain why it was important to me, he laughed....now he can see my son, but I'm there the whole time. I don't make it an ugly matter, it's just what it is: we all go to McDonalds playland or the park together).