We enabled the ability in version 2.1.20120711 to add a constant to your wp_config.php file that SlideDeck will look for to auto-populate and set the key for the license. You can do this for any tier, but it really helps when using the developer license and a WP Multi-site setup.
Here is what that would look like:
Just place this in your wp_config.php file before the following code at the end of the file:
/** Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');
Then replace the XXXXXX in quotes with your license key.
That's it, you are good to go. Each time a new site is created, the key is auto-populated and there is no need to enter it again.