Actually, spotters are sometimes more dangerous than not having a spotter. There are times when a park will insist on spotting for everyone that registers - and I ususally have no problem with that. And if I owned a park, and considering how badly many RVers park, I might do the same thing. Many have no regard for sprinkler heads, small fences, grass that is not a driveway, or whatever.
Spouses or partners develop elaborate sets of signals that I hope both understand. When a combo of a big rig and a spotter making many varied hand gestures parks next to me - I always go out to protect my rig. Just recently while in Laughlin, a lady was directing the driver of a big rig into a site next to mine that was not meant for that rig in the 1st place. As I watched, she was turning him into the site while looking at the other side of the coach than the one that was going directly into my right front corner. Rather than yelling at her, I yelled at the driver. I always make sure I can see and yell at the driver in such a case. I yelled at a spotter once, and she just yelled back at me while the coach continued on a collision course. Other times, the driver gets out and starts yelling at the spotter. Then I "know" I'm in trouble.
My other pet peeve with spotters are the ones that insist on spinning their hand/arm in the direction they want me to turn my steering wheel. This was mostly when I was pulling a TT and a 5thW. Nothing could be more confusing to a driver looking in his mirror for direction. When it happens, I just stop, go back and tell the person to simply point their finger in the direction they want the back of by trailer to go. I will then turn the wheel in order to move it that way. At a park in Redwood City, CA once, I finally told the park spotter, if he didn't go away and leave me alone, I was going to ask for a refund. With his directions, I was about to wind in the SF bay. ???