Is there any common knowlege about inclusitivity-vs-exclusivity of ‘till/until...

Is it “common knowledge” agreed upon by all native speakers worldwide that the word till can variously be used both inclusive and also exclusive of its end point, depending on the context?

So for example, in I am on leave till Friday, sometimes this means that I might still be out Friday but sometimes it means that I might already be back to work Friday.

Do native speakers realize that you cannot tell which is meant here?

This follows the same ambiguity as the usage of "until" in this context, and has been asked before.

I would assume that the sentence above is exclusive and means that the person would be in on Friday, though this seems to be exclusive to absence-related timeframes.