Just commit, no matter the response. Adding /s is akin to explaining a joke after you tell it. If someone doesn’t understand or pick up on the sarcasm, it’s not your responsibility to spell it out for them. You add /s because you don’t want to be held accountable.
I agree but also want to point out that as social animals we can’t help but care what others think of us. You’d need to be a psychopath to not care and I believe that even they do because being liked makes it easier to get what you want.