MongoDB replica set node failure without arbiter

I'm baffled by the fact that this is addressed in the official docs (or at my inability to track it down). From the 3.4 docs:

Only add an arbiter to sets with even numbers of voting members. If you add an arbiter to a set with an odd number of voting members, the set may suffer from tied elections.

So we have two possible scenarios:

1. A replica set with an odd number of data nodes, which requires no arbiter (and in fact, adding an arbiter can be detrimental per above)
2. A replica set with an even number of data nodes, and an arbiter

This is great so long as things are running smoothly. But what if a data node goes down in each of these scenarios?

1. We now have an even number of nodes with no arbiter. As I understand it this means you cannot have a successful election.
2. We now have an odd number of nodes, plus an arbiter. Above docs state that this can lead to tied elections.

This is so painfully obvious, why can't I find any discussion or documentation on it? But what I really want to know is, how do I correctly handle these scenarios?