It's a non issue. I could just as easily craft a client update that will create 50 billion coins and make them spendable only by me. This type of attack is possible on ANY coin.
Well I wouldn't say it's a non-issue if someone can create a client update that devalues a coin in an instant, even if that is possible with any coin, particularly as most clients don't seem to be GPG signed (the liteclient is and I'd like to see all clients adopt this practice) to help prevent users downloading and installing a rogue client. More that it's an issue for all cryptocurrencies, rather than a non-issue. Sounds a bit worrying actually.