Lupillo Rivera has no problem signing autographs for fans, but there are some items that he won't sign. After a recent event, the Mexican crooner was approached by a fan with a copy of his late sister Jenni Rivera's book Inquebrantable. The fan asked if he would sign the book, but Lupillo refused. The singer explained the encounter to El Gordo Y La Flaca, and said that out of respect to his sister, he has made a rule to never sign anything associated to Jenni. However, he does have one exception to his no autograph rule. Lupillo says that he will sign bottles of Tequila La Gran Senora. He explains that he believes Jenni would have liked for him to sign the tequila bottles.