I don't know if this has been considered or not, but players using wavebirds could also cause lag on Wi-Fi. Most wavebirds operate on the 2.4 ghz spectrum, however the original few operated on a 900 mhz spectrum. This could cause interference with the wi-fi system, and could definetly be something that nintendo did not forsee, as the gamecube could only go online with a wired connection, and when they were made wavebirds, at the time they did not imagine that their next console would utilize a wireless internet connection. When the wii came out i'm sure this came up in development, but the switch from RF to bluetooth for the wiimotes, as well as the stop of production of wavebirds, would most likely stop this problem.