When to Hand Out Handouts?

Example Handout (all rights reserved)
There is some debate about whether you should provide handouts before or after the session.  I like people to have something to scribble on; I don't want them to write down things I have already written for them; and I am happy to give people a moment to scan the handout before starting.  So I am happy to give them the handout before I start.

There is a risk that people will drift off while reading the handout, make paper aeroplanes, or leave, as they now have the essence of what I will be talking about.  I am happy enough taking that risk, as I believe that what I have to say will be entertaining and informative enough to keep their attention.

I wonder how 'the people who choose to hold onto their handouts until they are finished' would feel if they came to one of my training workshops, and I did not give them the workbook until we were finished.