Sloppy or Serious: I have to agree with that. The attitude of the person in that case would dominate their work quality.
However I think you are being overly cynical about the 'Senior Web Engineer' bit.
True, you can make it far by faking it. Very far in some cases. But number of times I have run into developers that only landed the job because of the habit you describe, I can count on one hand. Was there a particular event that shaded your world view so?