Frequently, people in a hiring position treat prospective candidates like cattle. They forget there is a human being behind that resume or portfolio.
All it takes is a reply like this:
"Hello _______, We are very appreciative that you took the time to send us your _______. Once we get a chance to review your ______, we will contact if you we feel like you are a good fit.
Best Regards,
_____________"
Works both ways in my experience. Whenever I was hiring I always got spammed by many candidates who were obviously sending out their resumes to large numbers of jobs without even bothering to read the descriptions or application instructions.
This reminded me of the time I got a Resume from someone applying for a software-engineering job. The guy somehow thought that putting "Sandwich Artist" as part of his work experience was valuable for his application. This, on a 2-page resume which could have been easily reduced to 1-page.
I got the resume before the first phone screen... he did not do well.
All it takes is a reply like this: