It has come to my attention that Pokemon Online does not follow the legal rules of IVs for legendary and unbreedable Pokemon. As opposed to say, Shoddy Battle, which disallowed the creation of illegal IVs for unbreedable Pokemon.
I'm not sure if the IV combination availability has changed from this generation from the last, but one thing is for certain: previous generation's legendaries are allowed to have any IV combination.
For example, say I created a Timid Azelf with 31 IVs in all stats, but a 0 in attack. Checking Shoddy Battle and PokeGen, this is an illegal combination of IVs for Azelf, making it an impossible Pokemon to attain, yet it is freely playable on the Smogon server.
The Azelf example may not have been the best in terms of importance to the actual play, but other illegal combinations may lead to minor advantages for certain other Pokemon. Despite this, the bottom line is that illegal Pokemon are being allowed on Pokemon Online.
I'm not sure if the IV combination availability has changed from this generation from the last, but one thing is for certain: previous generation's legendaries are allowed to have any IV combination.
For example, say I created a Timid Azelf with 31 IVs in all stats, but a 0 in attack. Checking Shoddy Battle and PokeGen, this is an illegal combination of IVs for Azelf, making it an impossible Pokemon to attain, yet it is freely playable on the Smogon server.
The Azelf example may not have been the best in terms of importance to the actual play, but other illegal combinations may lead to minor advantages for certain other Pokemon. Despite this, the bottom line is that illegal Pokemon are being allowed on Pokemon Online.