GTKY? Yes... and no. There's a bit of a lesson here, from either side... and even for someone who never becomes involved in something like this.
I was a 19 year old guy building a sand castle on a broad beach filled with vacationers. A little girl of about 4 was nearby at her family's beach mat. She was looking on with interest, so I invited her to help out. She did. This happened all the time - my sand castles were (and are) ambitious, but I didn't give orders, or control the kids - the beach was for fun, and there's little way to stifle fun faster than getting orders. Sometimes I would ask if they wanted some pointers, and of course I'd always be using the best techniques I knew, so as they watched me, they'd pick them up. I like teaching, so this was fun even beyond the challenge of trying to make a castle different than those I had made or even seen before. So, she made the castle a bit, went to swim, came back, changed, made more castle.
Fast-forward one day. I come down to the beach, and see the girl sitting on the family towel, crying. I figure the parents were okay with her making the sand castle yesterday, and would remember me; so I go back up and said hello. The mother did not see me approach, and kind of freaks out. She doesn't remember me from yesterday, even though I was making an enormous sand castle right in front of their towel for about two hours, with the help of their daughter and others. I try to remind her, but she still doesn't recall. She insists that I leave. Fair enough. I go down to the water.
A minute later, the father comes down and accuses me of being a child molester, and threatens me with death if I come near them ever again. He is clearly not under rational control, so I can't be sure he won't attack me on the spot. And he's stronger, and more dangerous yet because of parental protective instincts. I tense up, stand on the balls of my feet, spread my feet out into a defensive stance.
This was it. For all the posturing, if he had attacked, I would have run, but I knew he would have caught me. I had never been any good at fighting, and I didn't want to hurt him anyway - he was just doing what he thought was right, even if he was jumping to conclusions. Maybe he saw my sand-castle-building as luring. Maybe he had been looking at me yesterday while his daughter changed on the beach in front of everyone, and misinterpreted my surprised embarrassed look as furtive lecherousness.
Or he could have completely forgotten me from yesterday, so that the first time they remembered seeing me, I was approaching their daughter, rather than the other way around.
I figured that, given no evidence against me to explain away, I would do best with a flat denial: "I have not harmed your daughter, and never intend to. I have not asked her to reveal herself to me, and will not. I am not attracted to her." Nice and complete, if I could get it out.
When he finished his threat and asked, "Do you understand?", I instead replied with "Yes sir". It wasn't hate-filled. And it wasn't a lie - I did understand what he was saying. But it was defiantly insincere in its recognition of his authority, and expressed my readiness to defend myself against this accusation, by force if need be. Well, it expressed that, even if I wasn't really prepared to do anything of the sort. And it wasn't what I had intended to say. It didn't cover any of the points I was trying to cover - mainly, establishing my innocence so that the whole conflict could be avoided.
Maybe my front of being ready to fight was much more convincing than it seemed on the inside. Probably, it occurred to him that the beach guard would call the cops if he smeared me all over the beach. For whatever reason, he backed off and stalked up the beach before I could regather my wits and say my line.
In any case, I figured that correcting him wasn't worth the risk, so I rounded my corners wide for the next week so I wouldn't find myself face-to-face with them.
In thinking about this afterward, I figured out a lesson that I have followed to this day: If you want to make contact with a kid, and his or her parents are present, do so directly in front of the parents, and make dead sure that they know that you know that they're there. If you see a kid alone, and want to help, then be sure to deliver him or her to his or her parents so that their first impression of you will be that you are someone who is on the up-and-up. If they get a negative first impression, it'll be worth your teeth to get it fixed.
And of course there is the other side to it - be cautious, but please don't jump to conclusions. Some people do just like kids. There are plenty of responses which work equally well for either category.