How to display a warning message without preventing someone from saving

Hello,
Is there a way for CRM OnDemand to display a warning message without canceling a save?  Currently I have a workflow set up to look at a date field whenever someone checks a certain box - if the date field is less than 14 days the save is canceled and the warning message is displayed.  Now I'm being asked if the warning message can be displayed without the save being canceled.  I tried using field validation for the warning message, but it also cancels the save.

Thanks.