I think it would be only wise never to chose to show an indecent portrayal of any major religions God or a countries head of state. I ponder how far a naked statue of the Queen would have gone.
I truly think an artist does have free(within the limits of the law) reign in what they do but it does not mean it is acceptable to be placed in a public viewing area, there are private collectors they such art is better suited for.
The only thing I can see this being done for is to make a direct a statement of disregard for what others deem holy or just for shock value. Shock value is a marketing tactic meant to keep it in your mind.