When I got home from Backus (I live in Denver, about 1,000 miles) my hitch ball was chewed up through the chrome and copper plating, into the steel itself. Each additional use has worn the ball more - both on the trailer side and the TV side. this is after about 1300 miles 
Here's what Micah Eveland told me:
I do not see any issues with the marks on the ball other than you don't have any grease applied to the coupler or ball. With the ball and coupler you will always have steel rubbing against steel. If you don't have that you risk having the trailer jump off of the ball. Grease the ball and enjoy the trailer!
Yikes! the trailer might jump off? Still, I think he missed my point... and if it needed grease, why didn't his team apply it? They hooked the trailer up before I got out of my car, even. I asked that.... and his response almost made my head explode.
If the ball is ground down flat then perhaps your coupler needs adjusting but grease would have eliminated that. We only help you hook up and check your lights for an added service to you. We can not and do not control your tow vehicle's wiring, hitch installation, or grease.
As I am working on reducing stress, I dropped the topic... it clearly wasn't going anywhere. I asked about adjusting the coupler, as he suggested, but never really got a response. He suggested that I have a professional inspect the coupler, which I did..
We found that the inside of the coupler is not even remotely smooth - there are blobs of paint or welding splatter in there. I've cleaned it up as best I can without tools, and will probably sand or file it somewhat. The clasp - that part of the coupler that locks down on the ball - clearly has some wear, as well - you can also see the very-not-smooth surface at the top of the photo.
So, fellow Scampers - what do you think? Most folks who tow tell me they never grease their balls - after they stopped laughing at the question, that is :-) - does anyone on this forum use hitch or wheel bearing grease on their balls?
Also - have you ever adjusted the coupler? My hitch guy tells me that the ball is safe, just ugly. He suggested that I replace the ball once the inside is clean, but no sooner... or I'll just chew up another ball.
I'm eager to hear the thoughts of more experience Scampers...
The main thing grease on the ball is good for is ruining a good pair of Jeans. Joking aside, grease never hurt anything but a good pair of pants. It won't keep the chrome from wearing off the hardened ball but it may save a little wear on the coupler over the life of the trailer. This is what some people do, use dry lube, dryer sheets, grease or nothing at all. If you do lube the ball make sure you use a ball cover. Two things you don't want to happen. DW gets grease on her pants or you throw the stinger in your trunk and get grease on everything.
This is a good question for E trailer.
Eddie
I have never used grease on any of my trailers, RV or utility. On a long trip I would consider waxed paper over the ball before hitching but never grease.I do like the dryer sheets idea.
GREASE IS MESSY!
Kenny
Never have used grease and while many of the tow balls have dechromed on the top there isn't any appreciable wear and some are over 15 yrs old. If I used anything I'd do the spray dry lube that doesn't make a mess and get all over you. Certainly would be doubtful that it will cause any issues one way or another.
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I always use gear bearing grease to apply to the ball. The hitch drops down much smoother,makes less noise when towing, and just operates much smoother.
<p>Doug Allen 2016 Ford F-150 2018 Lance 1575</p>
I use dry lube, and have stainless balls on all of my vehicles. Stainless are not plated so there is nothing to scrape and peel off.
P.S.A. - Keep your balls clean
http://www.stainlesshitchballs.com/
We have pulled horse trailers, boats, a toad behind a motor home and large utility trailers over the last thirty years, and never greased any of the balls. three most important things: Correct size ball, proper height of the hitch, and secure the top locking mechanism with a cotter pin or bolt. We have never had anything come unhitched.
Rhonda Riebow
Tractor trailers use a huge amount of grease between their truck and trailer. I have towed boats, larger trailers, and have always greased the ball. As a one time aircraft mechanic, it just makes sense to me, that two bearing surfaces do much better with grease. I know my trailer lowers down on the ball much better, and makes less noise when properly lubricated. Grease the ball.
<p>Doug Allen 2016 Ford F-150 2018 Lance 1575</p>
https://www.etrailer.com/Accessories-and-Parts/Reese/58117.html They even have a video on it. One good point it lubes the release parts. Note: They also sell ball covers.