I did consider telling the parent in both situations.

For the younger girl I decided it was wiser to just explain calmly afterwards why it was wrong to do that. I considered telling her mother but decided not to because it was pretty harmless and I decided it was a can of worms I didn't want to open.

For the older girl it was much more overt and again I considered telling a parent but decided not to because it was frankly too embarassing. I put it down to hormones and didn't want to open that can of worms either.

In todays society its safer to just not get involved at all. Ethically I considered telling a parent because I questioned whether there might be something going on that the parent should know about. I questioned where such behaviour was learned so I did have some concern. But in todays paranoid society good acts can easily backfire so I just turned a blind eye.