Hi John,
The challenge you're having with reactive behavior is a common one. In the current work environment, proactive behavior is not rewarded the way it should be. In a ROWE, as you know, it pays to plan because time takes on a new meaning.
What you're doing with PTO slips is great - it reinforces to your employees that you mean what you say with "Results over Time". They have their own beliefs about work engrained in their heads about how they should do things - and to them, it's weird not to request time off for family issues, etc. We've heard people say they'll feel guilty if they just take the time and don't submit a request. Until they actually migrate to a ROWE, that is! Then they realize it's not about their time requests at all - the only question is whether or not they are delivering on expectations.
To help your employees understand where you're trying to go with them with "Results over Time", perhaps you could give them copies of Why Work Sucks. In our experience, it's not until people actually read the book that they really understand what the whole results vs. time thing means. Might be a good step to take...might also want to have a few key members of upper management read it, too :)
C&J

