Do you add a doom token when this happens? I've always played that you do, but now that I think of it, I'm not sure if there's any place where it says you should. Is there?

*cue mocking laughter

FAQ:

"Q: When a location card says “a gate and a monster
appear,” is a doom token added to the doom track?
A: Yes."

One other question that sometimes comes up with "gate and monster appear" -----

If the location is sealed, so a new gate cannot appear, does the monster still appear?

It's my impression, "no." The logic is -- no gate appears, so there's nowhere for the monster to come from.

I believe that's right, isn't it?

That's how I play it - the intent of the card seems to be "open a gate on this location as if one had opened here in the Mythos phase".

Glasgow Scotland said:

The rules themselves state how to handle that situation:

"Once these actions have been taken, the gate is now
sealed: No further gates can open and no monsters can
appear at the location of the sealed gate for the remainder
of the game." (p. 18)

So even a monster appears encounter would get nulled by the seal.

More complicated situations arise however that I am unaware of there being an answer for.

For example:

There is an encounter at Independence Square where a creepy man is walking off with a child. You hvae two options: confront or don't confront. If you confront the man turns into a monster and you fight. If you fight and win, you get a reward. If you don't, then the child is later found murdered. So if the place is sealed or Kate is at that location, no monster appears. Do you get the reward? Does the child die?

-Frank

Frank said:

Well in that situation, does it actually say that a monster appears? If not, then you still draw the monster to fight (if that is what the card indicates).

Here is the card in question:

Since a monster surprises you, you actually draw a monster from the cup and fight it. So if the location is sealed or it is Kate that pulls the encounter, the entire card is ignored.