Does Mageseeker Warden prevent units with Accelerate (like Sprite Mother tokens) from entering ready, and does it stop Thousand Tail Watcher from readying itself?

Ruling: Mageseeker Warden does not prevent units from entering the board ready. It only prevents exhausted units from being readied. Sprite tokens and all accelerated units enter ready and are not affected by Mageseeker Warden. Thousand Tail Watcher is also not affected because it does not "ready itself" in the way that triggers Mageseeker's ability.

Nuances:

• Entering ready is different from readying a unit - there is never a time where an accelerated unit is exhausted if the accelerate cost is paid
• Accelerate does not interact with or trigger abilities that are affected by units becoming ready
• Darius Trifarian's ability works differently because it explicitly readies itself