Ninjas are bad-ass (excuse our French). Everyone knows Ninjas usually wear all black. However, Ninjas wear red in 2 cases:
1) Their black garb is in the laundry.
2) The person the ninja is going after will be so startled Ninja is wearing red, he won't be able to defend himself or run away.
In any case, this mask is not really designed to be worn on actual Ninja missions, it's just styled to look like a Ninja :). Of course, whoever you are with can always pretend you are a Ninja, but hey, whatever happens inside your bedroom is none of our business.