The rape by executioners was a uniquely Roman twist AFAIK, but executing children to punish parents was not. For example, it was done to a traitor's family in 19th century Sri Lanka (repugnance at this helped the British overthrow the last remaining independent kingdom on the island). Probably many other places did the same.
> He said he had been a highly regarded member of the force, and had so "impressed my superiors" that, at 18, "I was given the 'honor' to temporarily marry young girls before they were sentenced to death." In the Islamic Republic it is illegal to execute a young woman, regardless of her crime, if she is a virgin, he explained. Therefore a "wedding" ceremony is conducted the night before the execution: The young girl is forced to have sexual intercourse with a prison guard - essentially raped by her "husband." "I regret that, even though the marriages were legal," he said. Why the regret, if the marriages were "legal?" "Because," he went on, "I could tell that the girls were more afraid of their 'wedding' night than of the execution that awaited them in the morning.
https://m.jpost.com/iranian-threat/news/i-wed-iranian-girls-...
From Tacitus:
It was subsequently decided that Sejanus’ remaining children should be executed, though the mass anger had abated and the majority had been placated by the previous deaths. They were therefore carried off to prison, the boy (Capito Aelianus) aware of his fate, the girl (Junilla) so innocent that she kept asking what she had done wrong and where they were taking her, that she would not do it again and surely could be punished with a trivial beating. Historians of the time say that as it was thought to be unheard-of for capital punishment to be inflicted on a virgin, she was violated by the executioner, the noose beside her; both children were then strangled and their young bodies thrown down the Gemonian Stairs.