A useful distinction
Publishing an event date before confirming a venue can create a misleading impression of readiness. A calendar is more useful when it shows which steps depend on others. Proposed and confirmed dates should remain distinguishable.
Put it into practice
List the necessary prior decisions beside each milestone. Mark tentative dates clearly in internal records and public drafts. Revise communications when a dependency changes rather than keeping an obsolete date because it appeared in an earlier attractive design.