Similar story - end of season travel soccer tourney. I'm reffing an u-9 girls game at 7:45 am. Grass is dewy. Players are small and slipping. Lots of slipping and one dad wanted a tripping call for ALL of them. He was sporting an XXL cup of Dunkin', all fired up. It reached a point where I did a very long and loud whistle to stop the game at a throw-in, calmly walked over to coaches, called them together and explained if that parent doesn't stop the abusive behavior, whoever's team he belongs will need to explain that if it doesn't stop, he will be dismissed from the facility for the remainder of the tourney. One coach then said, not sure he'll be a problem anymore, as the asst ref had sidestepped down the line and quietly talked to him. Turns out, the asst ref explained to the dad that if he continued, he would be ejected and my favorite "this isn't the World Cup, they are 8, it's slippery out here." Of course, the dad said "you can't do that", and the asst ref (my hub) said, you are correct, but she (me) will ask your coach to remove you from the facility and the game will not restart until you leave. The dad didn't say anything negative after that. And this is why to this day, I disagree with any travel teams below the u-11/12 age grouping, just my view.
Fast forward to today - started coaching u-10 rec soccer after a 24 year hiatus (woo hoo, grandkids!) and the changes are interesting. Parents now encamp along the field at practice, which is a bit unnerving to me, as they never did that years ago. Times have changed, perhaps it's a safety thing, and I'll get used to it. No chatter from them during practice, however my hub (trying valiantly to avoid getting into coaching again, haha) saw a parent from opposing team throw down his water bottle and loudly complain numerous times when his son/team didn't do something "right" during our game yesterday, or when the ref didn't make calls he thought should have been made. Glad I didn't see/hear it and glad it's not one of my parents.