The island would soon be rid of the rats. If they don't denounce Allah, then they are crippled or beheaded. Their numbers would soon shrink. The only Muslims left would be the "good" Muslims that don't break the law. I predict alot of conversions if they had to live under that crap. Why did they leave home in the first place?
This is the same principle we are using in Iraq. We are getting rid of the people that would vote the "wrong" way, slowly but surely. Soon their will only be "democrats"(small d), left to vote.
"This is easy! Just have 2 justice systems. If they claim to be a Muslim, cut out the tongue, cut the hands or feet off, stone them, or just behead the rascals. If they claim anything else, just use existing justice."
Worth repeating.
Of course, in their minds, Islamic law means they cannot be punished for what they do to Christians.