Interview Question: The job requires you to _____. Is there any reason you could NOT meet those requirements?
This is the perfect way to learn about things like second jobs, transportation issues and even possible childcare coverage problems. For the most part you can’t directly ask about these issues, but you can ask this question and act on the responses. So asking someone to tell you if the need for them to be available to stay late or come in on weekends is an issue is acceptable. If they then tell you they cannot meet that requirement because of any of the aforementioned issues you generally are on solid ground to eliminate them as a candidate. Be careful not to provide possible answers, instead saying silent and allowing the responses to voluntarily flow.