Problem with Spain is, the borders are porous and crossable, no way to maintain it, and being EU, forget it.....The EU is understandably very very worried and demanding info from Spain. Too late....The EU is like a big boiling pot of broth, it will get everywhere.
I agree w/your assessment of the problem w/European borders...but both symbolically and practically, shutting down flights from WAfrica could stem the tide. Doing something is better than doing nothing (at least in terms of citizenry panic).