I have always had girls that played previously for me to wear their team shirt to tryouts. Our different age groups even got on their player group text and coordinated what color each team was wearing so that the new girls to tryouts could tell the age groups apart. I think in a sport where most people assume you have a core group that this should be expected of returners or girls that are hoping to return. Now I wouldn't send my DD in her team gear to another teams tryout, she would wear a tournament shirt from the bazillion she has in her room.