From your description, they kinda sound like the sort of people you can't tell anything to until after they've screwed up. Even being newbies, I'd think they should have read up on it and known how to hook things up and what's ok and not.
We see guys like that in RC training too. There was one 2 years ago at my club. Showed up with an RTF foamy trainer. Said he'd watched YouTube videos and been flying on the sim so he was ready. An instructor strongly suggested getting on the buddy box or at least having an experienced pilot trim his plane for him first. He refused. On a side note, he didn't have his AMA or club membership, so per our lease regulations he shouldn't have been allowed to fly on his own. But I wasn't privy to the conversation until later. He took off, promptly made a hard right turn, and scattered EPS all over the roof of the pit area next to the parking lot. After some colorful language, he said he was getting a refund because the plane was "ready to fly."
Now I know that the best thing to do is leave the guy alone and let him think it out over the next few days. But sometimes I just can't resist a good burn. So since I just happened to be the closest person to him while he was retrieving what he could from the roof and still going off about how he got gipped and was going to complain, I calmly told him, "Piloting skills aren't included in the box. Just because the plane was ready to fly doesn't mean you are."
I managed to survive that exchange, and he left. The craziest part is he came back about 3 weeks later, having bought another foamy. The whole refund thing didn't work out after all. He again refused help (both incidences were on training day, so instructors were everywhere) and again flipped his plane over and crashed it. This time, I brought up the AMA situation with the instructor who had talked with him and we had an impromptu meeting about following rules so we don't lose our property. The guy never came back.