Thats debatable especially with Liteons lack of QC.
Remember all that you really only need to scan once per media type (not every disk) unless you have issues with playback. For data dvds all you really need is a transfer rate scan and a surface scan for errors.
In an idea world where suppliers and manufacturers are consistant, that would be true. However in the real world where atleast ~80% of media sold has fake MID codes or is B/C/landfill grade overprinted to look like grade A then I'm afraid regular quality testing is a must.