Other than obvious copyright issues, there are many with scanned decals. The Arrow version above is very low resolution, at least from a pixel count. If you crop the main part of the logo, it isn't even 500 pixels wide. I do pixel to pixel to vector conversion in Illustrator all the time and especially for fine detail, like the bow, you really need a lot more pixels. Parts of the bow are only 1 or 2 pixels wide. Hard to get very good results with such a low resolution. A cursory test of that logo, even after preprocessing in Photoshop, yielded poor results.
Scans at 1200 psi are obviously better, but unfortunately many scanners are really just 300 or 600 ppi, and use interpolation to get higher pixel counts. That can cause another set of issues.
And very few decal scans have any kind of physical reference for scale or color, which further hinders accuracy. Even when I have scanned my own decal sets, converting them to vector art can be a very tedious process, even with software like Illustrator which has very good pixel to vector conversion abilities.
Tony
I tried to convert the NASA Pegasus model decals to vector (37518) and the Pegasus was really a bear based on how small it is on the original decal sheet. I basically had to redraw it from scratch.