Yeah, unfortunately it was probably the screamng.
Screaming was absolutely forbidden around my father - inside or outside. The only exceptions were if the house was on fire or when we were on a roller coaster. (His 11th commandment was "Thou Shalt Not Annoy the Neighbors).
Sadly, that rule did not apply to his wife ;)
Nice of you to be concerned about the neighbors. You sound like a very kind person. I think most people wouldn't have given TSN (The Scowly Neighbors) a second thought.
If they had walked over to you and said "Your kids (doing whatever activity) is really bothering us", would you have done anything? (Just curious. Sometimes a nice request goes a long way. Other times it just eggs on the behavior of people who think they're "entitled" to do whatever they want anytime they want.)
EDIT: Btw, I'm sure that almost all of us here have a story about "How I p*ssed off my neighbors while camping". Either accidentally...or on purpose. :)