It is in fact discussed in the book. GTD is great for procrastination if used wrongly, because only adding stuff to the lists isn´t going to complete the tasks.

It is in fact discussed in the book. GTD is great for procrastination if used wrongly, because only adding stuff to the lists isn´t going to complete the tasks. Also, it is important to note that GTD isn´t a fool proof system. Without constantly reviewing the tasks and checking whether tasks should be added to another list, the inbox piles up and then the system doesn´t make sense anymore.