I have seen it in a race with a semi-rival team doing it (typically red, changed to black right before the gun). Our team realized it about 400m into the race.
I can only really speak for myself, but the only thing I did differently was scoff. The other team had a better race than anyone expected, one guy in particular, and sneaked into nationals.
The general consensus was the it was a hilariously pointless, but at the same time they DID make nationals.
This was a DIII regional race.
Separate story:
I went to Buffalo last year to watch the DI NE regional. I don't know if they had changed on the line or had them on the whole time, but Columbia had black uniforms instead of their typical fairy blue. Again, I can't speak for anyone else, but as a spectator it took me more than half the race to realize this and I simply found it to be annoying. Good thing I wasn't a parent, I would not have been happy with the coach if I couldn't spot my kid for most of the race.