Books and Student Success

I wonder how much the simple requirement to buy books affects students in a course. What I mean is that students need to buy their books online. If a student delays signing up for a course until the day before a class begins. Then the student has to go online and buy books (often opting for mess that priority postage), it seems that they will usually not get their books until week 2 of the course. That gives them a hurdle that they are already behind.