Many teams adopting Kanban come from Agile background. Agile thinking has discouraged the use of Due Dates. Due Dates breed undesirable behavior. Focus on Due Dates results in teams working under significant pressure. Quite often, that translates into short cuts in Design/ Testing activities. The net effect is that work quality is compromised and technical debt piles up. That said, Agile methodologies, specifically Scrum, inherently have a Due Date. Most often, this is the Sprint end date.