How would you deal with this?

Any time you are directed to do a group project, you can ume that the actual purpose of the exercise....at least in part, is to see how you work with others. Group projects are about being able to work with others, they can get real sticky, different personality types....different ideas about what is appropriate. If I were an instructor I would think much of someone who omitted others contributions and turned in an ignment without consulting the entire group. It speaks volumes about how that individual deals with the complexity of day to day life.