That's what the law says. However, in the real world, it's still up to the CO. Results were about 50/50 on this one. If the CO thinks the spill looks "suspicious" - and that's totally up to him and his interpretation - he may still site you stating you put the corn there...he doesn't believe it was a spill. Then it's up to you to prove your innocence. Pray the owner steers you to the right share-cropper - to the right driver - and they remember it spilling...which they won't because they don't remember them all and certainly don't see them all. So, yes - technically legal - no, you may still get a citation.
Revenue............