if you type a cloud name that exists but doesn't have a card...

[peacekeeper]

then the cloud name is added to the list with an error symbol, which is good.
but the popup doesn't refresh automatically, only when it is re-opened.

in general, i think being able to add a card that doesn't exist is not a bad thing, because the cloud name holder may at some point in the future create the card, and the plugin will automatically start following it.