Yes, they literally do (or hire consultants to do it).
I went to school with lots of people who ended up in management consulting. One in particular worked at Deloitte and specialized in "human capital".
Most of their projects were to figure out how an organization could drastically reduce pension/retirement benefits for existing workers legally, while also offering much worse plans for new hires that looked good on paper.
They were paid around $1,800/day/consultant for all of these cost-cutting projects.
(This is not at all an uncommon story in the enterprise consulting world, by the way.)
I don't know the specifics of this case, but maternity leave is absolutely something that has been abused. My spouse worked with a woman who got hired while she was pregnant, had the baby and took advantage of the company's extremely generous paid maternity leave, and then came back in and quit on her first day back. From the company's standpoint, this hire was simply a cash giveaway and a huge loss.
The key word is here "already earned". Denying that doesn't make any sense, any which way we look at it.
Still, punish the 95% (or whatever very high number) for the shitty behavior of other 5% of people? I understand it is business and companies need to protect their profits, but this is ridiculous.
Yeah, I agree. Just pointing out that this stuff rarely comes from mustache-twirling villains and more often is just a misguided attempt to solve some other related problem. Cutting off commission that has already been earned sounds pretty bad.