DeMarco Rule of Life #74: The Check Out Scanner Malfunction ParadoxOr Why Things Go Wrong When You are in a HurryDaniel DeMarcoMay 13, 2019·1 min readOne common source of unlikely events. Image courtesy of Wikimedia commons. No machine-readable author provided. SchuminWeb assumed (based on copyright claims). [CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)]. What that just said.For any errand, the probability of unlikely events is inversely proportional to the amount of available time.