My first year I worked a JV game that my son played in. Very unusual situation, and everyone knew in advance. I took no grief, but it was VERY close all the way and little fun for me. (Long story, previously documented on this board.)
I now work the 7/8 grade games for my school with no problem. (Its a Christian school, and I am on the board of the church that operates it.) My normal level is high school, but I treat every game the same. Point is, when I step on the Junior High/Middle School court, a level of professionalism comes with me that exceeds what they (fans, coaches, everyone) usually see. This makes a big difference (in my opinion), and I'm normally treated very well. (Hope I don't have to retract that statement in a few days....
)
As for observing poor behavior, that is disappointing. I see this sometimes when sitting the stands as well. First, remember that forgiven implies the need for forgiveness. We are not perfect -- none of us. Second, maybe there is an opportunity to speak to someone at a later time. I'm in that position, but most people are not. Maybe it makes sense to share your observations with a key leader in the organization. Maybe you can't. Either way, we have to push on beyond the situation. Good luck.