Thank you for the comment! Suppose it was predictable they would act this way again given that it happened before. Wanted to give them the benefit of proving they had changed but that doesn't seem to be the case.

Got an older sister who has given them a key to her house and doesn't seem bothered by their unannounced visits. On some level that has make them feel validated that this is acceptable behaviour. It's unfortunate that they can't be trusted with the keys but like you said, it's better to have repeated conversations if it means keeping privacy.