Give um a ZERO!

Well, yesterday we had a big discussion on giving students zero's for missing assignments. The argument was to either give them an incomplete or a 50 for a hundred point scale. I feel that if the grades are weighted correctly, giving a student a "0" will not significantly hurt their grade. I also feel it is our jobs as teachers to teach responsibility in that a student should know that if they do not do an assignment or refuse to, they will be given a zero for that assignment. I do believe in allowing a certain time period to make up the assignment but anything past that time period, the student gets a zero. How do you feel about giving students a 50, which is a fail on a 100 point scale, compared to giving them a zero for not turing in assignments.