Blocking people from completing the project before the tasks are done.

So we work a lot with projects in the organisation and it sometimes happens that people will put the project on completed without putting the tasks on completed. This is a bummer since I am working with the automation function that needs all the tasks to be completed. If that is the case it will change the status of the project to the next stage before it can be completed. So that is why it would be nice to have something that can prevent people form not completing the tasks.