I'm trying to add a multiline custom field as Chris mentions in his comment on this thread:
I've selected "rich text" but I don't see an option to make it multiline.
Where can I do this?
Dewey, I read that to mean if you make it a "rich text" entry field then the guest will be able to use multiple lines in their answer. (That's why he is suggesting you tell them to use one line per guest.) I don't think he means you can create multiple entry lines for the same custom field.
Yes, that's correct - currently you can't force-create multiple entry lines for the same custom field. If you use the "rich text" field type, then that at least allows the guests to create multiple lines.