I pray it wasn't a small child, waiting for his or her mom or dad to cross the finish line. My heart breaks just thinking about such a thing.
I imagine it was a person, whether adult or child, holding them, then accidentally releasing them upon such a startling and frightening situation.
What I take from seeing those yellow balloons is HOPE. Yellow is traditionally known as the color of hope. And while I do not understand how someone could create such terror, nor do I understand how the people in Boston feel, I do understand the power of hope.
I believe those yellow balloons were a complete symbol of hope. Hope for those people near the finishing line today. I imagine those yellow balloons to still be floating high above Boston, soaring through the air like a dove. And I imagine the strings of the balloons eventually settling to the ground like an olive branch, bringing peace and a fresh start to those in Boston tonight.