Within the privacy options, I would like to have an option to log only blocked queries.
This option exists for the query log. Admin GUI > Settings > API/Web Interface > Query Log. Were you looking for something other than this? If so, what would your proposed privacy option do and where would it fit in among the existing privacy options?
Apologies, I hadn't seen that option.
Except it isn't the same, this is only a fiter to show blocked entries, once you flip the permitted domain entries everything from the past is also shown. I agree, I would like a blocked domains only logger. I don't need to see what everyone normally visits.
Closing in favor of: