I own my own guild. They don't know. I tell them that my kids play my toons, and they aren't allowed to talk when they play. I also tell them that it's part of the reason I have a guild, because then the kids don't get harassed. The 3 people in my guild that know are my wife (duh), my RL friend of 15+ years (he bots too, because of me) and another RL friend, that's likely to start botting. If he does, then there will be 4 people that know, because of his wife!
I used to let my guild know, and I have a banned account now. And no amount of petitioning has helped to this point, been banned a year. My wife and I are fairly certain that the guild drama queen reported the botting. Shortly after I got banned, she got guild leadership somehow and booted all my toons and all my wifes, along with about 3 or 4 other friends.
So no, it's not good to tell your guild.