My goodness not this old wives tale AGAIN. In the Unreal engine, high pingers CAN NOT LAG THE SERVER. There are other game engines where that is not the case, which is why you will see people from games based on the Quake engine (Source, COD, etc) say these things. But people with high ping have no affect whatsoever on the server. I've been doing MP network coding in Unreal for almost 10 years, and I've dug into the deepest guts of the Unreal engine network code and I know exactly how it works.
The server uses a certain amount of upstream and downstream bandwidth per player. Every CPU cycle it receives information from clients, and sends information to clients. No matter what your ping is, it always sends the exact amount of information. On the receiving end, it is simulating the player movement physics and other things for all players every CPU cycle regardless of their pings. When it receives information from a client, it compares that information to its simulation and then sends corrects to the clients if there is any discrepancy. But these fixes for discrepancy still have to fit into the outbound bandwidth that the server reserves for each client, and the checking calculations are done every time data is received (and actually would be done MORE often for a low ping player since the server is receiving client updates more from than than from a high ping player).
In 10 years working on Unreal I have NEVER found a server admin that could prove that a high pinger lags their server. Every time they say this happens, it actually turns out that the server admin was running too many player slots for what their machine could handle. So it didn't matter if it was a high pinger or a low pinger, once the server had to many players on it it lagged out because the CPU was overloaded. But because of this silly old wives tail they always blame the low pings, and not their lack of understanding of their servers capabilities for the problem.
The only thing that having a high ping hurts is the high ping player themselves. Because they won't get updates from the server as often, but since the server is simulating their position and sending it to other clients the other clients wont see a difference. Unless of course the person has massive lag and packetloss, in which case the other player will warp himself (but not cause other players to warp). This still gives him no advantage though.