That's a possibility, but unlikely. Twitter execs were probably well aware of the long arm of the law and that their ability to stay in business to a large extent depended on staying on the right side of the line legally. That's precisely why you see them arguing about this to such a degree in these articles, they are well aware of their position vis-a-vis the law.

I've had some contact with the FBI over the years regarding stuff happening on one of my sites and they were - it has to be said - polite and arguing their case quite well, in no way did I feel like figuring out whether if I refused them what the next step would be, it felt like I would be the unreasonable party. But if they had made an unreasonable request I would have told them to fuck off.