Usually a request to user>attacks returns { "attacks": { ... } } where the value of "attacks" is an Object, but when "attacks" should be empty (e.g. /user/?selections=attacks&from=[some timestamp from the future] ) it returns { "attacks": [] } where "attacks" is an empty Array.
I have only tested this with user>attacks so it could be happening in other places too.
I have only tested this with user>attacks so it could be happening in other places too.