Sure as its a setting on the account, but thats not something you can personally do about it, like i suggested just changing your DNS server to a more reliable one will resolve the error search issue, but the question is, if you type an invalid domain why wouldn't you want it to provide search results to help you attempt to find the correct domain?
Just curious as to why you would even want to specifically disable this feature, you're still using the virgin DNS servers which can still technically hijack DNS records at their whim should they ever choose to do that
I don't want to get those error messages, it just annoys me to see it. Also i've been experiencing really slow dns query time from their servers, i prefer using google or another provider. I'll probably need to get my own router as theirs does not allow me to change it for all users.