Balloons, for all their festive playfulness, are dangerous to kids, especially those under 8 years. Since 1973, 110 kids have died from sucking balloons into their airways.
Children 8 years and under should not EVER EVER EVER EVER be allowed to blow up a balloon. They hold the balloon up to their mouths and then deeply inhale and the balloon quickly gets sucked down into their throats.
They chew on pieces of exploded balloons or hold pieces over their mouths to blow bubbles and the latex is sucked down their throats and over their windpipes.
Babies chew on balloons. They explore their world by putting things in their mouths. When the balloon pops, they gasp in response to the loud noise and again, the pieces get sucked into their throats.
Obviously, your judgment plays a key role. If balloons are to be placed well above the crowd and there's no risk of kids getting their hands on them, it may be safe. Your call.
Balloons, especially the Mylar type, cause a remarkable amount of power outages when they wrap around electrical lines. Of course, many balloons end up in the ocean where they become lodged in the throats and bellies of marine mammals. Just sayin'. I don't think crepe paper ever killed anybody.
Yep, I'm a party pooper...