I think it's accepting context and intent. I if I say 'Half the time when I get to work the door is ajar' I'm not claiming to be precise. To your point, since I didn't give the expected error for my claim I'm not attempting to be rigorous or precise by saying that fraction. If you jump on my back and say 'it's actually only 30% of the time that we leave the front door to our business open all night!!', then you are just failing to adapt to the way everyone communicates in a very bad faith way, and holding onto some false belief that you are 'technically correct'.