I suppose there will never be an end to the need to remind authors to make sure that their book announcements are letter-perfect. The blurb they provide will be the first sample of their writing anyone will see and if there are mistakes in grammar, spelling, punctuation, etc. this will not give a prospective reader a very good impression of what their book might be like. After all, if you cannot write a single paragraph carefully, how good can the entire book be? It's exactly like making sure you are well-groomed before going to a job interview.