I agree that having them is unfair and here is why
- If they are absurdly bright they can be seen easier and give you away easier
- You can easily tell what weapon it might be from further away just based on the color
However I believe having community voted and approved skins that are more matte color and not bright, is totally an awesome idea. Skins should be allowed but ones that aren't going to give you a visual advantage over a newer player just because you play gmod 5000 hours like me and know how to modify files compared to the new player with 1 hour on the server trying to see you in hicktown trees and you see him better because of the skin.