If you or i sign up, would we get special treatment not to go to iraq, NO! why should he, so what if he is a royal, he is not first inline to the throne, and not that being first inline to it really counts for much these days, the royals are more a public figure than important decision makers of this country.
For hundreds of years leaders of there country's have sent everyday man to fight on there behalf, i dont see why they shouldnt fight for there own country also.
If he got captured there will be a big media circus of how silly it was to send him, if he dont go it will be oh he gets special treatment, so he cannot win and for that i do pity the guy cos its not of his own doing.
1 thing that i would be suspicious of, is if he did get killed, how long would it be before the politicans spin came that it was iranian terrorists an lets go start a war with them.