This depends on how you define "if you skip past". You can see it in two ways:
[*]element gets focus, you change it or not and it looses focus when you go on
[*]an element that is in the form at some point after this element gets focus.
We implemented the first interpretation because it is easier to implement. The input order is also not necessarily clear from the order of php function calls so your approach is a bit harder to implement. You can create an issue on github if you want the second approach to be added as an option. You can also try implementing it yourself and send a pull request.
As I said, it is somewhat more difficult to program, however in my experience a form is normally completed from the top down. I have myself created forms which function in just this way: If a user skips a required input it immediately throws an error. Far more user friendly.