Gmail shows response suggestions to emails I haven't responded to yet. I would like to disable them. Can it be done? If so, how?
Great news! As of October 2018, Google have finally relented, and now allow Desktop / Web interface users to turn smart replies off.
It's about half way down the default "General" settings tab, under Smart Reply. Turn it off and you will no longer get the red automatic suggested responses buttons.
While you're looking at settings, if you're the kind of person who prefers not to have your emails written by a robot, you might also want to check that "Smart Compose" (autocomplete for emails) is also turned off. That's also in the General tab, about a third of the way down.
As of early summer 2018, Gmail does not offer a way to disable the "smart-reply" feature in the web interface per this blog post.
However, users have reported being able to conceal it using AdBlocker. Refer to this Stackoverflow thread for instructions how.
Best I could tell, you can't disable the "smart reply" feature in the web interface (as of this writing: Sept 7, 2018).
However, if you use an ad blocker (e.g. uOrigin or Ad Block Plus) or other plugins (e.g. Custom Style Script) that can mangle the web page, you can block them.
I added a custom filter of:
mail.google.com##div[data-message-id]+div table .brb
Additionally, I tried disabling them from the mobile interface, but that setting doesn't seem to affect the web interface. Discussion here on google group also seems to support that they can't be "disabled" in a proper way within Gmail.