General quality of vector files

Is there any professional quality control being done before accepting files for sale? The quality between files varies greatly and often cannot be assessed from the preview image. Take this file as an example (137104567😞 half of the lines don't meet correctly, with ends stopping before the other line or overlapping. That makes the graphic pretty much unusable in any size larger than a postage stamp. And because everything has been outlined it's very tedious to clean up. 

Certainly this kind of quality would not be acceptable if it was done by an illustrator/designer for a client.