NOTE: My "steps to reproduce" above on RiffTrax.com will not work since I have fixed this issue on our site (with core caching enabled - still no solution for Boost yet).
I have found the issue and a solution. No cookie is set until a user submits the add to cart button for the first time.
See my Issue here: http://drupal.org/node/679422
(We need to add a uc_cart_boot() to uc_cart.module.)


