No, GTD neither requires nor encourages putting due dates on tasks which do not have deadlines by which they must be completed.
Your review process is what ultimately drives completion of tasks without due dates. If you see a task that should be worked soon, use the flagging feature to mark it. Each day, make sure you complete everything that is due for that day, then work your flagged actions and items coming due in the upcoming days.
Your review process is what ultimately drives completion of tasks without due dates. If you see a task that should be worked soon, use the flagging feature to mark it. Each day, make sure you complete everything that is due for that day, then work your flagged actions and items coming due in the upcoming days.