Thanks GamTak 
Slotplayer, in answer to your question: Free games (on flash) will be blocked.
This is a summary of how the blocking will work:
1. US will be removed from the countries list in the registration forms
2. Attempts to open new accounts from a US IP will be blocked, in case that a US player chose a different country in the form
3. All Flash play and progressive play from US players will be blocked. Flash is blocked as there is no way to control IP access in Flash while it is possible in Viper + Flash is a very small percentage of game play in the US
Hope that helps…
Thanks, Lloyd