Time wasted "preparing to copy files"

When dragging a big folder over to a folder you don't have permission to write to on another disk, the "preparing to copy files" can take a long time before the copy begins, and when the copy begins it stops immediately because you don't have permission to write to that folder. Assuming it's always quick to check permissions, do this before "preparing to copy files" part, so that time's not wasted "preparing to copy files".