For the Milwaukee Regional, Team 857 bought facepaint. I told the students that they could paint their faces but to limit it to that - no full body painting. When they asked why I told them:
1. It's not appropriate to run around the venue without your shirt on; mostly because it's potentially damaging to our team image. What if one of our sponsors saw you and thought, "I'm paying $8,000/year for these kids to run around half-naked?? No way!"
2. You won't be allowed in the pits and we might need you there.
3. It's cold outside! You'll need to put your jacket on anyway to eat lunch (and your mom will kill you - and maybe me - if you come home with blue paint all over everything)
If another team wants to paint their bodies - go for it!
As for my team, I'd rather have them running around with blue faces and our team shirt on (which has our logo, number, sponsors, etc) than with a big "8" on their chests.