Well, have them back up their claims with an account that has the reset. Like how Raifudo had his second Raifudo account rp steal his RaifudoMakashi's sharingan eyes via role-play and could trace it back to said account.
lolwut?
Raifudo has his eyes via RP with another's eyes; some random Uchiha, if you prefer. RaifudoMakashi didn't role-play for that purpose, he was just the account that leveled and had the reborns to back up the fact that I earned it.
Disregarding the position one is in, even with a multitude of Kekkei Genkai/reborn or the nifty RP claim [bijuu, swordsmen sword, etc., etc.], it's not so much about who has the most, but who can use them the best.
If you feel someone is god-modding, etc. call them out.
That simple.
You feel like they're god-modding, calling themselves invincible, yada, yada, just don't fight them/ignore them.
Nothing is forcing you to do so.