Trying to make sense of late penalities

As I plan for the coming school year, I'm trying to make sense of late penalties.

A typical policy is that students lose 10% per day for late work and no late homework is accepted.

On the surface, this seems to make sense. Kids need to learn responsibility. Getting work done on time is an important skill.


But there are two problems with this.

1) Imposing penalties doesn't teach anything. It doesn't show kids who lack the skills how to manage their time and get things done on time. And while it may motivate some students to "kick it into gear," others--those most at risk, don't respond that way. They're used to failure. They expect it. That's the problem.
And we're not helping them. At the very least, we need to accompany the penalties with support and training until the start seeing success.

2) The second problem is that it places an inordinate amount of value on turning things in on time. What percentage of a student's grade should be determined by whether or not they can turn things in on time? In our system, a student who is routinely late by a couple of days on major assignments could easily lose 20-30% off the top of his or her quarter grade. Should timeliness be worth that much? Should we count time management and responsibility as 30% of the course grade, especially when we don't even teach it?

Right now, I'm looking at ways I can increase support so that students don't fall into this trap. But I'm hoping in the future we can do something completely different.