My DD (17) & I take the small bottles of Wedding bubbles to the parks. If we see kids in line that are getting restless, then we get our bubbles out and start using them. But if we bring them, we bring extras to give out.
A box of Wedding bubbles isn't that expensive and the wand is on the lid, so you don't have to worry about dropping it in the bottle.
If we don't have extra bubbles with us, then we have stickers to give out.
We were telling a good friend of ours about taking the bubbles to park and she has a 3 yo daughter and we were at a friend's wedding. We talked to the friend and any extra bubbles, she got to take to the park for her 3 yo. They thought it was a great idea.