What are some examples of such "straightforward social cues"?

I would genuinely like to know, because the only social cues at coffee shops I have seen pre-Square terminal have been super context-dependent. For example, you tip if it looks like the baristas are kind of overwhelmed – e.g. at a super busy time like the morning rush; or if you waltzed in with a large group and ordered seven lattes or something. Because the baristas are gracefully operating under pressure and getting the coffee to you on time, you tip them.

After Square terminals, it seems like tips are expected even if there is literally no one else in the shop because the app says so. Which is not really a social cue.