he had a great time. First time pulling the trigger but he did real good. Also had my granddaughter there 13 yo). She was pretty apprehensive at first but after the fist round was lit off, she loved it. Hindsight bring 20/20, what more could a grand father ask for? The incident did nothing to spoil thier day....

The RO in question with the silver hair asked whether your grand kids took hunter ed because he mistook you for another shooter who he was helping originally and was trying to make small talk with you. Usually, if a child IS shooting center fire and is being questioned as a "corrective action," then the shooter or responsible adult is guided to the rules board to review the rules.
When the taller RO, who I admit, has a little more aggressive approach to enforcing the rules, came over to your bench, it was because the original RO and he HADN'T talked about whether your grand kids was or wasn't of age and had to do his own assessment. The fact that he hadn't said anything meant he didn't see anything wrong.
This seems like a complete misunderstanding. However, we never stop anyone from initiating complaints, there have been misunderstandings and complaints in the past. And every RO, as well as veteran range users, know that it's the RO's job to watch EVERY shooter utilizing the range at any given time.
It's really damned if you do, damned if you don't for ROs. They exist to make sure people do not leave with any additional holes in them, and sometimes--a lot of times--brings out the ego or what not in people.