I am not a fan of using sites like Seeklogo or Brands of the World to get corporate artwork assets. Very often the logo files that are uploaded are re-creations done by other people. The files aren't authentic.
It's one thing if someone is using a company logo in a personal graphics project. But if the artwork is being used in a paid, commercial project then it's vital to have authentic, current art files as well as color specs and brand use guidelines.
If I'm in a time crunch and need a company's logo immediately I'm more likely to find legit corporate art elements within PDF documents posted on the company's web site. A company like Calvin Klein might just as likely rasterize any logos within company PDFs to prevent people from extracting vector-based elements to re-use.