Option 4 Bob produces invalid XML file and gives it to Avery. Avery's permissive parser that he wrote in an afternoon reads it MOSTLY fine, but gets a few thin

Option 4 Bob produces invalid XML file and gives it to Avery. Avery's permissive parser that he wrote in an afternoon reads it MOSTLY fine, but gets a few things wrong. Avery goes on with his work not realizing some of the data is incorrect, and Bob doesn't need to pay a contractor.