From the Dec. 16 Globe and Mail:

(Muntadar al-Zaidi of Al Baghdadia satellite TV) gained his privileged access to Mr. Bush on the strength of his accreditation as a journalist. Without it he would have been like any other anti-Bush protester, chanting unheard insults behind barricades and a tight cordon of security. The price for this access was a duty to treat Mr. Bush, as with any other news subject, fairly and professionally. He owed that to Mr. Bush, to Mr. Bush's Iraqi hosts, and frankly, he owed it to his fellow journalists who rely on news conferences like the one he disrupted to carry out their work.

The moment world leaders think they will be the target of projectiles thrown by reporters is the moment that the privileged access will end, not just for Mr. Zaidi, but for other journalists as well, harming the vital work of a free press.

Yes, to maintain privileged access, journalists should never throw anything hard at world leaders -- especially questions. :)

More seriously, I do concur with the overall sentiment. That type of behaviour is way outside the bounds of what should be considered acceptable.

Addendum

This BBC story has more aftermath news: Bush brushes off shoe attack