There are numerous differences from a tax-funded maternity program and insurance. (the hope of) free markets determining insurance prices, ability to opt in or out of specific coverage, the source of funding to name a few.

The point isn't to trust people not to scam the system (because just like banks have found another way to abuse (now commercial) mortgage backed securities (CMBS)[0], market dynamics can be applied to people finding a way to abuse the system), but to design such a system best we can that gives the benefits to those the program is intended for, and to prevent abuse from malicious actors.

[0]: https://www.propublica.org/article/whistleblower-wall-street...

A better example is a 401(k) match. I make contributions that maximize the amount my company matches. My benefits agreement says if I contribute up to $X I’ll get $Y. If I precisely contribute $X am I screwing my employer? It feels almost like I am gaming the system!

I take all the vacation days I’m promised, too. I precisely time it so I use every last day. Screwing my employer again!

Ya, but drawing maternity leave and forcing your employer to keep your position available to you upon the end of the leave and then telling them at the last minute that you don't plan on coming back is a little bit different. More akin to using sick days when you aren't sick, imo.

But government programs could fix this by paying maternity leave whether or not the mother plans to go back to work. Then they could be open with their employer that they don't plan on coming back.