The current plugin code already can detect outdated versions of the smartctl program.

I suggest improving this practice and signaling the lack of sudo configuration. 
Usually the sudo command also displays a special message:

sudo: a password is required
 

But Smart Plugin return  json parse error:

Cannot fetch data.: failed to scan for devices: Cannot unmarshal JSON.: invalid character 's' looking for beginning of value.

This creates a problem for administrators unfamiliar with the specific agent errors.