In my experience, packet loss does not happen too often. When it does, it seems to happen in bursts. Reordering seems to be much more frequent.
However, most important is that it can happen. For a simple game state this is not an issue (simply drop the old state and interpolate), but you really need to be prepared issues with game events (e.g. chat messages, kill events).
Most net-libs (DirectPlay, ENet, RakNet) implement a way to mark packets as 'reliable and ordered', thereby ensuring that packets arrive and are sent to the application in the correct order.
I would say it really depends on what you'd define as 'roll through'. From the few I looked at, I think many candidates would have their answers be marked as incorrect. They're quite full of small gotchas, instead of really testing someone's programming skills.
(But hey, that may just be my disappointment speaking )
That said, I'd be much more interested in why the candidate gave that answer. If a candidate knows what a reference, copy constructor, initialization list, etc. is, but just overlooked some small issue, I'd still would want to hire them.
Example: one of the tests checks if you know what happens if a local functor has the same name as a function and you call f(..). I don't care: anyone who programs something like that will be close to be fired on the spot or at least have a good talking to...
So as a test, I don't think these are particularly good. As a starting point for a technical discussion, they're quite nice.