Don't see why not, I'd do mine in neon pink/electric blue
Cause I like the medieval feel of crpg. hence why I hate the brightly coloured flags ppl use on their heraldic sometimes: We just did not have access to cloth dyes so easily in medieval times, sure in asia they had some nice colours and in europe others etc: but the cost of getting the dye or the material shipped would mean that it would be reserved for fancy events, you would not put your best and brightest coloured coat on over your armour, you want something in subdued colours and hard wearing, not electric blue silk etc...
also neon was not a word then, think about why that was huh? neither was electric, if the NAME of colour you want to use is already out of place, how much worse is the ACTUAL colour itself huh?