Then again, maybe your co-workers regularly — as in, weekly or daily — abuse your gullible boss' generosity to avoid paying for regular day care. Another possibility — the only one that entitles you to complain to the boss — is that you're consistently required to make up their shortfall at the expense of your own sanity. One worker's right to work-life balance does not trump another's.
Absent those last two scenarios, however, it sounds to me as though your boss simply trusts his workers to meet their responsibilities. Speaking as someone who once was a child-free worker, I think you should be grateful to have a boss who is trying to create a more humane workplace — not just for folks raising children, but for any worker with a parent, partner or pal who someday may need looking after.
Karla L. Miller writes an advice column on navigating the modern workplace. She has written for and edited tax publications for 16 years, most recently for the accounting firm KPMG's Washington National Tax office.