not really, lagg goes both ways, one person ''laggy'' to server, both are in the pvp.
what u do goes to server, then to player. ms to a player is ur ms + the ms of the other person.
in a fps, everythin is checked on the server, but in mmo's (not all, but a vast majority) the clients do most of the location/targetting.
hence how ''range attacks'' happen, if some1 is constantly hittin another person melee they get stun locked on the attackers client, but to the one being attackd, u may have walked ages away, n think they are ''range hacking'' lol.
lagg will only cause a pvp to be really stupid, if some1 is constantly 1.5k+ ms. or if you have fps issues.
ANYWAY lol, back to le topic at hand.
you would need to offer something in return to people before they would let you host it on their pc.
otherwise, your more likly to either get no one to do it, or some one will, but down the line, they will remove your db, mess with it, and fuck you over probs.