>Seems to me that we should try to make life easier for users, even human ones who make mistakes?

Yes, I agree.

>To see why this could be a problem, enter a bunch of data in a field and press Ctrl-0. Bye-bye data. Pretty annoying especially if there's no reason for users to enter null values.

But surely there are all kinds of key combinations that can cause errors? Did you ever press Enter when you didn't mean to (I have)?

I'm not saying one shouldn't trap Ctrl+0; just that if this is a real problem, then the company needs to hire better data entry people. If they're pressing Ctrl+0 when they meant to press Shift+0, then they're probably pressing Shift+9 when they meant to press Shift+8, etc.