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.