I disagree. The phrase that implies that the button will be pressed, provided that it is enabled – but otherwise not - is "Press a button only when enabled".
That is one phrase that certainly does state that intent clearly. But... so what? That phrase isn't used as the name of an action and that isn't what the action in question does.
My suggestion relates to the existing name of the action "Press a button when enabled". I do not think the name accurately sums up the purpose of the action, so I am suggesting that replacing "when" with "once" would bring more clarity. "Once" has fewer connotations in this context.
I expect you to answer my calls when you are home.
I expect you to answer my calls once you are home.
That similarly conversational example illustrates that "when" is not always exchangeable for "once". But that's surely no surprise. Let's focus on the context of KM actions. Try this:
You stated what "press a button when enabled" implied to you. That is a matter of pragmatics, not semantics.
To me, "press a button when enabled" is ambiguous – and I misunderstood what the purpose of the action was. If I am alone in finding the phrase ambiguous, then of course the matter is closed. But either way, we are talking about pragmatics.
It had indeed occurred to me that "once" is also a little ambiguous, but:
The names of actions must be kept short, so of course none of us will want something of the pattern "press a button if it's enabled now, or once it becomes enabled".
Nobody would benefit from such a name. Nobody would think "oh, if the button is now enabled, this action will wait till it's disabled, and then enable it".
Not that I mind (it's all fun ), but again the discussion has turned to theory. Let's get back to the practical aspect, which is all that matters: is "Press a button when enabled" clear enough (to a sizeable majority of people!) in its meaning – and if not, is there a succinct, practical alternative?
I think any answers to this based on instinct will vary (maybe by region?). But it is the instinct, the intuition, that is more immediately important here than linguistic analysis (fun though that also is).
Thanks for your replies so far. I hope I have clarified the reason for my suggestion.