Don't let all your trombones be boys.
Don't let all of your percussionists be the GT kids.
Don't recruit only girls to play clarinet.
Don't put all of your LEP kids on trumpet.
Things like that. If you don't, all it will take is one year of aggressive recruiting from your volleyball coach and you could lose an entire woodwind section. Same with football.
Mitigate future student loss. You will lose 10-15% of your kids per year, more between 6th and 7th grades and then 8th to 9th grades.