I have seen many cellphones do this. Plus, the Kompakt already already allows us to block calls from hidden numbers, to block calls from unrecognized numbers, and to build a blacklist of incoming-call numbers to block.
I am asking for the ability to block text messages from unrecognized numbers (i.e., “Only allow text messages from your saved contacts”).
And, you have another good suggestion: the ability to block text messages on a “Blocked Numbers” list (a blacklist).