Final answer:
The default behavior in MATLAB is 'hidden off', thus the statement is false. Users must specify 'hidden on' if they want obscured lines and surfaces in plots not to appear.
Step-by-step explanation:
The statement that Matlab defaults to the behavior of 'hidden on' unless 'hidden off' is specified is false. In MATLAB, the default behavior is that the 'hidden' setting is off, which means that when plots are generated, the lines and surfaces that would normally be obscured by other surfaces are not hidden.
However, if a user wants to enable the 'hidden on' behavior to ensure that the visualization properly reflects the obscured parts, they will need to manually specify 'hidden on' in their plot function calls or commands.