I already experience those, 2-3 weeks without waggering and get those 10$. The third weeks decrease to around 6-7$. It really can, but not guarentee at all... I consider mys elf are kinda lucky to get those. For getting 10$ without waggering after 1 weeks is possible but for 2-3 weeks without waggering to get the 10$ without decrease is not guarentee however is still possible based on my experience.
I'm going to do the experiment again to confirm it. I had received around $17 in the previous week for playing with deposits. Then I got $10 from this weekly bonus without any deposit, while my wagering activity was too low during this bonus period. And I'm not going to make any deposit or wager before the next weekly bonus. Perhaps, I will get around $6-$7 from the bonus.