Are you sure? I never noticed that. As an experiment, I did this in an ssh session from macOS to OpenBSD:

    stty raw; cat

... and while every key I tried now had its literal effect, including enter producing only a carriage return and Ctrl-C, Ctrl-V etc. producing their control characters (I think, I cannot see them :) ), <enter>~. still terminated the connection. Lucky terminal combination maybe?

Hmm, I just tried it with stty raw and you're right.

It has happened to me though. Maybe a curses crash can leave it a state other than raw? One of the other modes such as inlcr plus ..? Also I suspect smart terminals and shells prevent a interactive session from getting too crazy.

Yeah, come to think of it, it wouldn't really surprise me if some weird terminal state swaps ^J and ^M or something.

Edit: Oh, you mentioned that yourself already, inlcr.