Dr McNinja III: You Rad Bro?

[Silver Swift]

Another factor reducing Connservation of Ninjitsu here is that both ninjas have very distinct costumes, not just in colour, but also in overall theme.

Exactly, Conservation of Ninjitsu is only an issue if you have enough people that anonymity becomes a problem (named people are better fighters) otherwise there is still the same amount of Ninjitsu on both sides.