According to this university site (section dedicated to bracketing commas):
There are a number of common words which typically introduce weak interruptions containing complete sentences. Among the commonest of these are although, though, even though, because, since , after, before, if, when and whenever.
Example from the site:
Columbus is usually credited with discovering America, even though the Vikings had preceded him by several centuries.
The author says weak interruptions typically contain complete sentences. So I wonder if, according to this rule, you can use incomplete sentences as well. Example:
She'd never let anyone hurt him, even if that meant sacrificing her life.
I wonder if by typically the author is implying that sometimes these interruptions are not complete sentences.