Unless of course you aren't allowed to reset into [any of] the Sage Arts; as Ice had previously stated, those already possessing KG's may test them on the beta server - such a law may/-not be passed onto the live server, so don't go jumping to conclusions.
Similar to Ice, I do not RP with people who claim to possess KG's they haven't reset into, and am less inclined to RP with people boasting a stronger prowess over their KG than their number of resets into said KG implies (i.e. Claiming Haku's prowess in Hyouton whilst being a simply 'Snowflake'). If you're really that desperate for KG's, take one that isn't augmented into the system (like Yoton {terribly overlcaimed} and Shoton {like Yoton,though to a lesser extent}).
Oh that, no that doesn't mean they are available to all. Neji just made it that way so anyone can test them, that will mostly change when they are released for real.
Oh, dang. .-.; Though I'm sure he won't since we've seen Madara have both Sharingan and Rinnegan; but I'unno.
Madara also has Mokuton, so to be a complete [major] antagonist rip-off, one would need to have maxed the Sharingan, the Rinnegan (considering he can access all six paths) and Mokuton (well, probably not).