Yes they can if they are running a number of scripts, which this one most likely is.
Here is a good and simple definition of latency I found online:
“Latency, measured as ping, refers to the average total time that it takes your gaming device to send data to the game server, and back to your device. Latency is measured in milliseconds (ms) so if your ping is 100ms then it takes 100 milliseconds for your computer to respond to a request from the game server.”
This person is sending massive amount of data to the game server and back due to the amount of scripts which he is most likely running and hence causing massive amounts of latency in the instance, or in whichever part of the game he is running them.