I was never cut out to be an artist but one thing I've heard from people in that trade is they'll eventually wind up taking some pretty weird gigs.
There are so many people out there who want bring a particular vision to life and if they can't do it themselves, they'll hire someone who can. Although artists can sometimes find good money in taking commissions that cater to specific niches, that can sometimes come at the cost of drawing things they wouldn't even want to imagine.
And as we'll learn from one strange story out of Illinois, even G-rated material can sometimes land them in complicated situations.