I've seen places that have that minimum be mandatory. As in, if you haven't taken a vacation by a certain time, they will insist, even go so far as restricting access until the vacation is over.
The great thing about a mandatory minimum (never thought I'd be saying those words), is that it doesn't allow someone to over work themselves into a frenzy, making everyone else look lazy, while simultaneously burning themselves out.
In countries where vacation time is mandated by law, restricting access during vacation time, and ordering the employee to enjoy the vacation before its expiration date is common practice.
An employee who fails to take vacation on time or goes to the job during vacation time is actually a liability to the company.
It's also a somewhat hilarious contrast to those companies who take away your vacation time if you don't use it within a certain time period (often just 1 year).
"It's also a somewhat hilarious contrast to those companies who take away your vacation time if you don't use it within a certain time period"
This is pretty standard in the UK. If you're a permanent employee, your annual leave allowance (e.g. 4-6 weeks of holiday) covers a period of one year. If you don't take that leave during the year, you lose it (you're unlikely to get paid for the untaken leave).
Some companies may allow you to carry over some of that leave to the next year (e.g. a week) or may allow you to "sell" or "buy" some extra leave. However, this normally needs to be done at the start of the annual leave year so requires some pre-planning on the employees part.
