If a user starts with Stack Overflow and the first question they ask gets 100 down-votes, is it possible for that user to achieve a negative reputation score?
This question does indeed differ from How does “Reputation” work?, and is a new and valid question. While that other question is a general inquiry as to the function and nature of rep on SO, this question asks specifically for the behavior of reputation and downvote effects at scores close to zero.
In particular, so the FAQ says what happens to the reputation -- but not what happens to the downvotes occuring at a time when a user has +1 rep. But what about those downvotes -- are they just nullified? Effectively that means that a downvote on someone with a rep of 100 has an effect, but a downvote on someone with a rep of +1 has no effect, ever.
This means that users with +1 rep are effectively invulnerable. They may have no privileges, but they are invulnerable.