What bothers me most about that is 'harmless'. As if he were an animal, or an idiot, someone who could be seen as a threat. He's a teenage boy, and whilst he may be autistic, he is not irrational or crazy or senseless. I almost think it's worth pointing out to your neighbour that because of his autism, Charlie is more likely to take rules as absolutes, that he is completely unlikely to enter a house without permission and that leaning over the railing is not the same as climbing over. I would personally point out that her daughter perhaps needs better understanding of what autism actually means rather than overreacting but I'm short on patience for the passive-aggressive >_>