I bought my Nexus4 specifically as it is NOT tied to a carrier.
So did many others, and it doesnt matter. As Telstra Australia users have found, if you have their sim in the phone, Telstra restricts the updates - even though the phone wasnt bought through Telstra. Want the update? Simple drop another carrier's sim in the phone (who isnt restricting it - ie any other Australian carrier), and the update is instantly available. Update - return back to your Telstra sim. (I believe Telstra has started rolling out the update recently however.)