Dear LW: Do not apologize for your daughter's "mistake" (or pay attention to Abby's advice in general). Tell your sister she needs to pretend to be a mature adult for one minute and get over this. She is not being excluded. She is being asked to help control the spread of a deadly pandemic.

Also, she gets to skip a wedding! Weddings are a pain. She should count her blessings, pour herself a glass of wine, and enjoy a comfortable evening watching Netflix in her PJs.