I have a few teacher assistants in the university, and when possible we try to cover each other and keep the class going. Some problems are not related to kids.
* When the parents die, sometimes you must go all the previous week to the hospital. Or in a better scenario, you have to help your parents to go to the doctor.
* Some unexpected or chronic health problems. Sometimes small changes in the actives distribution can help.
* Problems with the car, for example after a small crash you must take the car to the official mechanics of the insurance.
* One of the water pipes is leaking and it is "raining" in the apartment bellow. The plumber promised to arrive in an hour...
* A trip to a conference or a similar event.
It sounds most likely to be 'reciprocity', but could also be evoking either the notion of 'reaping what you sow' or the notion of 'paying it forward'
I guess the question is: Do you believe that you should receive benefits above and beyond those of childless adults because of your life choices? That the act of becoming a parent is so sacred it should grant you benefits in otherwise unrelated areas of your life?