The max amount of characters from the same IP that can attack another player is 2. This was  posted in news. You must have missed it.
I assure you, we are checking for bots and banning them. There were over 130 bots banned in December.

Wilderness

1 IP fixes: We have implemented more secure measures to prevent Multi while in a 1 IP zone.
Fixed bug where you could use territory bank to access your personal bank, using the quick gear buttons
Loot from kills while in territory will now go directly into territory bank.  This will make fighting for the territory more appealing again.
Edgeville Dungeon and Above the level 48 fence-line will be permanent P2P. Godmage will rotate in those areas. The rotation will be 1 day with God Mage and 2 days without God Mage.
F2P Wild permanent from level 1 to the level 48 fence-line. NOTE: Ranging Guild and Red Dragon Aisle will remain P2P areas
IP check for Team Fort is no longer blocking shared characters. Team Fort remains 1 character per IP limit.
Fort timer has been changed back to 5 minutes before you are able to enter on a different character.
East Wild has been changed. 1 IP has been removed and this zone is now 1v1.
Effective immediately, no more than 2 characters per IP can attack a single target (range/mage/melee). Team Fort (1 IP) and East Wild (1v1) are the only exceptions, as they each are under their own restrictions.
You can no longer mage or range your own character in a 1v1 zone, in order to prevent being killed or attacked by another player
Bug fixed where you were able to catch your target in the wilderness before the wait time was over.