Thank you for your response to question about eating in kosher kitchen in non-observant home. May I ask you a follow-up question: Is there any practical difference between their trustworthiness here and the fact that they would not be “trustworthy” as aidim, say for kiddushin? This question has been posed by someone close to the situation; I do not know how to answer this.
Thank you vet much.
For kiddushin you need “testimony” which can only be given by kosher witnesses and even if they are kosher they cannot be related to each other (Even Moshe and his brother Aron could not testify together!). But in your case regarding kashrus in the kitchen all we need to know is that they are “trustworthy” and not trying to deceive us.