I guess at some point Steem will add a spam filter in the feeds for smt's!
Everything is possible, but I don't see the SMTs as spam since they're a product of Steem. Spam will always be a part of this platform unfortunately. Check musing-io and you will see tons of spam. I guess it's on us to filter through it and upvote only what we consider.
I was thinking more like Gmail style filter. The Steem feed that each of us have could have the option to separete Amy's. Of course we already have the option to 'mute' users which is quite similar.