My own experience with hybrid classes reminded me that students lead very busy lives and don't always read the syllabus, course calendar or moodle shell. I found that even though I had given all the dates for the assignments and I wanted them to be independent learners, that they did not always do assignments on time. I then started to send short reminder emails (using the moodle news forum), trying to be positive and motivational and discovered that the submission of assignments in a timely manner seemed to increase.
When discussing this with students they felt that the reminders were helpful in keeping them on track and made them feel that I really cared about them and their success. This was especially true when the tweaks or nudges had some positive content (ie. After our discussion in class, I look forward to reading your papers) rather than simply a reminder message.
This strategy also worked in classes that meet on a weekly basis. Why not give it a try?
Here are two recent New York Times articles that talk about the the good, the bad and the ugly of tweaks and nudges.