Is it sinful to avoid bothersome aunts who practice witchcraft, if the purpose of doing so is to avoid their harm while maintaining kinship ties?

If aunts are involved in sorcery and similar forbidden acts, they should first be advised and reminded that sorcery can lead its practitioner to the point of disbelief (kufr). If they do not respond and insist on their actions, then there is no blame in avoiding and shunning them as a deterrent.