I've been to quite a few workshops of different flavors. In the end, I can say that anything I prepared wasn't all that relevant or--in other words--what there is to learn, you will probably learn.
There'll always be at least one person more clueless than you and the important stuff will be reiterated for that guy or gal. :)
Just make sure that you remember or write down the recommendations that are specific to your swimming. Apart from that, the only rule seems to be to enjoy the experience. So, have fun! :)