Hacking is illegal for these reasons:
- Nintendo did not created the AR, nor wants the games of its company to be hacked. Game Freak as well.
- AR is for weaks. If you play for your own with no use against friends or online, then it should be fine. Otherwise, your reputation decreases when you hack or cheat into the game.
- If someone wants a Latias and someone else hacks for getting shiny illegal 31 IVs Latias level 100 for a trade where there are no balances, like a level 100 Greninja, then the person with the Latias is stealing the Greninja, as the hacked Latias is not hard to obtain, unlike the level 100 legit Greninja.
Grosso modo, what you have to understand is that if someone hacks and trades to other people who play legit then this is
Hope this helped :D
~ Yours sincerely, Blitz of Justice.