Hard limit =
Do not do this to me EVER.
$ACTIVITY is fine until it crosses this line.
To me, "hard limit" = "Do not do this to me EVER". Example of my hard limits - scat play. Do not poop on me EVER.
I had someone classify that second option as "hard limit" to me, as in I should have said that $ACTIVITY was a hard limit. To me, if something is fine at lower levels, it's not a hard limit. To this person, if it's something that you would potentially safeword out of at high levels, it's a hard limit.
We seem to be having some difficulty arriving at a definition for "hard limit". I have always heard it defined as Option One. But I was raised by wolves and recognize that my insticts regarding societal-type-stuff are not always accurate, so I'm throwing this out to you guys for a general consensus.