I think you're drawing a false distinction here.
First, there's no requirement that signalling be costly. If there were, then "costly signalling" would be a redundancy. We engage in cheap signalling all the time.
Second, a signal given to "gain the societal safe harbor protection" is still signalling. Indeed, this is a common motivation for signalling, displaying signs that tell people "I am one of you, I fit into your community and satisfy the conditions you expect of your in-group."
First, there's no requirement that signalling be costly. If there were, then "costly signalling" would be a redundancy. We engage in cheap signalling all the time.
True enough. Many are, though, and differential cost between accurate and inaccurate signals is important in such cases. Non-costly signals get subverted more easily. And, most of the time, non-costly signals are merely cheap, not free, or have a high cost at low probability when faked (for example, lying on your resume).
...Second, a signal given to "gain the societal safe harbor
The article can be found here. While it is not, for many of us, new ground, it is an excellent treatment, and it requires no rationalist background in order to be understood. The subject is the pernicious pull of doing the standard thing, regardless of whether or not the standard thing makes any sense, and it does us the service of giving that phenomenon a descriptive link we can share as well as an excellent name.
I hope to, after more discussion and thought, write a main post on the subject.