Unfortunately, there are still people in 2015 that use WiFi for fighting games online, and will tell you it's perfectly ok, while they don't get that even though their DL/UL speeds are good, their ping goes from low to high randomly just because it's how this tech works : it's unstable, period.
It has been proven, there are COUNTLESS threads / posts about this, but people either can't use an ethernet cable (too far from their router etc) and never heard of powerline adapters (for real), or just hate cables and prefer "no cables in their perfectly designed house" ... and bitch about lag spikes.
Then there's the small number of people that genuinely think that using WiFi is ok, and on par with using an ethernet cable, with reasons like "but I never had trouble with WiFi playing Mario Kart before" . . .
PLEASE give us a way to filter WiFi players, so that they just stumble upon each other, and have fun with their WiFi hiccups as a group.
It's been long enough we have to suffer these guys ... every fighting game brings more and more people using WiFi ... blacklisting all of them isn't a viable solution anymore.