If you consider the situations that would lead to the husband needing the wife so badly so as to need to override the wife's choice to not have the ringer already on, the subset of such situations which are life-threatening for the husband are probably situations in which the wife either can't assist in time or isn't the only person who can assist, so overriding the silence isn't required for life.
In contrast (and yes, my intention was contrast), if the wife was hiding from a shooter then her ability to maintain silence is required for life. Airplane mode isn't great, because she should be texting/tweeting/etc.
Thus, best to not let your silence be overridden.
For non-life-safety reasons that the husband might be trying to reach the wife, that could be solved via agreement ("keep your ringer on except in emergencies") instead of brute force.
