1: if I want to advertise on social media about how good the food is at a restaurant that my friend owns, am I required to inform everyone about my connection to the restaurant? Would it be gneivat daat to recomend the place without informing them of my alterior motive, even if I truly do believe that the food is good? 2: in a similar vein, if I ask someone to borrow a shovel, do I need to inform them what exactly it’s going to be used for, or will they assume its for some kind of shoveling? Thanks so much!
ב"ה Shalom Taking things for granted is very common today, therefore your questions are important. In regard to advertising on the social media, I consulted with a prominent Talmid Chacham who told me that according to Halacha you are not required to state your relationship with the restaurant owner. Also, since you truly believe that the food is good you are not lying or misleading anybody. This is under the condition that you are not restaurant critic whose job requirement is to be objective. However, we also discussed aspects of social etiquette which you may want to take in consideration, lest people find out in the future that you are is friend. People may possibly look at you as not being objective or dishonest. The mishna says (שקלים פרק ג, הלכה ב) that a person must come clean in the eyes of people as he comes clean in the eyes of G-d. In regard to your second question, it is a totally different issue and comes under the laws of borrowing. In this case one may not change the use of the borrowed item and if he does he is fully liable for damages.(רמב"ם הלכות שאלה ופיקדון פרק א, שולחן ערוך חושן משפט סימן ש"מ) Happy purim