I once invited my brother to play with me on Islands, and found out while we were playing that he was hacking. Honestly it was nothing but an annoying inconvenience for me, and now I refuse to play with him. He's my brother and I love him, but even having him on my team, hacking just ruins the game for others. I didn't trust any of his items, and all the weird glitches and lag drove me mad. Worst three hours of Minecraft ever. He ended up getting banned, and I honestly can't say it's not a good thing. He's not a bad kid, or a bad player- he just made the game suck for anybody on the server that day.