My two cents on the incident happened to your family at the Falls: You can say as the following: "You are upset because your baby has been squished by my backpack. I would’ve worried about my child if it happened to us. I do apology for the unintentional brush, but I am pretty sure nothing is sharp inside and outside of the backpack. Would you like to check your baby to see if she doing is well? (You need to have a parental consent to touch the baby, so just let the parent do his job). (Meantime you stay calm and say something sweet about the baby, “a cute, sweet baby, very well-behaved baby…”)” After the checking, “I am glad your baby is doing fine. I will be more careful in such a crowded surrounding. But if you can have your speech and tone in a more socially acceptable manner, I believe we both would’ve felt less frustrated. I hope you’ll enjoy the rest of the day.” Here is the pattern of communication: 1, point out his emotion (this is very power strategy to deal with emotional arousal people, usually, when you correctly label the emotion of the person, he/she will be quiet immediately which leads them to think how they respond to their own emotion, whether it is appropriate); 2, empathy, put yourself in his shoes, feel the frustration and concern of the parent; 3, apology; 4, harmony; 5, give a clear behavioral expectation. In most of times, people behave in such way just put themselves down and humiliate themselves in the public, nothing was wrong from your side in this scenario and you did everything you could to accommodate them. Cheer up, Sis!