Richard I must be getting some luck then. In most of my games using that template I'm less than 10 turns in with 2 blockades already.
In Strategic 2v2's, you start with 28 pieces/player and receive exactly 1 piece per eligible player per turn (on your team- so 2 pieces/turn). If you read the settings, you'll notice that each available card is set to minimum 1 piece/player/turn and that you receive exactly 5 pieces/player/turn- given that there's exactly 5 available cards (Reinforcement, Order Priority, Order Delay, Gift, and Blockade), that means exactly (min: 1, max: 1) piece of each card per eligible player per turn. It takes you 0 turns to get your first blockade (56 pieces available on Turn 1) and then 12 turns to get your next blockade if both players on your team manage to expand each turn (56 + 2 * 12 = 80 pieces- 2 cards- available on Turn 13).
This means you have 1 blockade card maximum through the first 10 turns, and 2 blockade cards available starting (at the earliest) turn 13.
No amount of luck makes it possible for you to have more than one blockade card available for your team prior to turn 13.
Are you sure you're playing on the Strategic 2v2 template?
Edited 6/16/2015 13:55:34