From what I've been told by a local LEO in PA, anything not offered by the manufacturer is technically
Most states (if not all?), as NiteRider said, make it illegal to have red and/or blue on the front of a vehicle,
or blue anywhere. (unless for show use only)
But as for extra yellow, amber or rear facing
red, a lot has to do with the mindset of the officer.
If it's not too distracting to other drivers, they may let it go.
If, as they say, it's a bad donut day .
the LEO might get picky and, as in the case of your friend, pull out the citation book.