Since I am the coach above that you are referring to let me answer that....
In my experience these are some of the questions that I have had to answer in situations like these...
" Why is Susie's mom wearing Team X's t-shirt?? Is she not at our gym anymore??"
" Susie's dad says Team X goes to 7 competitions why don't we??"
" Coach I do not think it is right that Susie's Mom is cheering in front of our team with Team X's t-shirt on go tell her to take it off...."
And these are just a small sample of the termoile that this situation causes...It really does I have lived it....And these do not include the multiple times the parent sits in my viewing area comparing me to them...or the team chemistry that the parents upset because the parents use the view area, team emails, team parties, COMPETITIONS, etc as a time to give a commercial for Team X. Or the countless athletes that are lost because of the recruiting of that parent..AND YES THEY DO RECRUIT!!!
I have this situation right now and we do all we can to just focus on the sibling that we train....So asking parents who have clearly showed that they do not care what the name of the gym is they are just picking based on the "need of their child" it is RIGHT to ask you to not upset the entire team because of your choices and please just stick to cheering on YOUR child.....