Interesting question.
Our school colors are blue and gold. Our robot team shirt is black.
We always promote ourselves as Carl Hayden Falcon Robotics and the school and students are proud of the club.
Our first year, however, we wanted a t-shirt that would stand out and look "cool", something the students would want to wear. Currently, black is the "in" color so we picked black. It has worked well for us.
Another tidbit. We would send out press releases and when the local newspaper did a story on us, they only mentioned 3 of our four sponsors. The fourth wanted to know why we didn't credit them also. Well, we had, but the reported dropped the name. Other times, there would be no mention of sponsor. So we decided to put sponsor names on the
FRONT of out t-shirts, so when they take a picture, there's the credit to those who support us.