I am looking for Chinese 成语 that generalize 袖手旁观, but indicate complacency with regards to something that could happen, rather than to something that has already happened, or is happening.
Current answers to my post mention war...
May be a strange distinction to make, but I was not talking about war. I was thinking about the occurrence of an undetected natural phenomenon, such as a flood, earthquake, meteorite, volcano eruption, or anything elder of the sort that one could not have accounted for, because there were no signs, and nobody thought about it. So I am looking for a saying imploring to think about a possible calamity when everyone else did not think it was obvious or coming. These things have all happened in history, unaccounted for, until someone was wise enough to think about them and get others to do so as well, and 成语 correct millennia of wisdom, so it seems strange that no-one would exist to describe what I am looking for, with all the 成语 out there.