Be aware that parks are always crowded and if your children are not used to crowds, you need to take extra care.
Dress your children in flashy clothes like neon colors or even a comfortable costume of the favorite character, so it is easier to keep an eye on them. It is also important for children to know their parents phone numbers, if they are too young, or even to make you feel safer, place a bracelet on them with their name, your name and phone number. So you have an extra guarantee that everything will go well.