Not in D/P. Last time I checked, my Mimic Glitched Space Breaking Mew goes right through it. No I don't cheat. I was testingI thought Nintendo made some sort of barrier that prevented hacked/cheated Pokemon from being used/traded online? If I'm wrong, just battle with friend codes.
Which do you think (out of curiosity) would be a fitting punishment for those trainers who use hacked Pokemon on Wi-Fi?
nothing but a warning. People who complain about hacking piss me off more than those that hack. If a hacker can disguise his Pokemon (ie, legit moveset and stats), then there's no problem, but anti-hackers still complain about it.