> Responding to "can you..." with "I can but won't" is generally obnoxious behavior.

It's a prod to get people to say what they actually want, instead of asking a vague questions with a stronger implication because it waters down the actual meaning of the words and is as weaselly as the response. Asking for the ability, requesting an action and giving a command are different things. Doubly so in hearings by government officials.

"Will no one rid me of this turbulent priest?"