The Importance of Profreading
The error in the title is deliberate, for two reasons.
First, it’s important to proofread everything, including titles, recipient names in a memo, captions for diagrams or pictures (see below), footnotes. It’s particularly embarrassing if you spell your client’s name incorrectly or your managing partner’s.
Second, prof for proof is a play on words, prompted by the experience of students at the Faculty of Law at the University of Toronto.
A certain law professor (who will not be named here – but who is identified in the original story) copied and pasted exam questions from a previous year. He seems to have failed, however, to ensure that references to parties and other details in the recycled portions matched up with the newer part of the fact-pattern. Exam questions were ‘so poorly written they were incomprehensible’. It sounds like there were problems of composition and editing, as well as proofreading issues.
Problems like this often occur when you adapt a precedent, or cobble together something new from multiple templates: defined terms that aren’t defined or are never used, inconsistent terminology, cross-references that don’t synch, problems with formatting and numbering.
There is software that will help with this (Contract Companion comes to mind) – but it won’t spot that error in the managing partner’s surname. 
A BC trial decision went to the SCC at least in part because the judge’s cutting and pasting made it just a bit too obvious that he was copying without attribution the plaintiffs’ counsel’s written argument; including the misstatements of the evidence. However, my favourite sloppy proofreading story involves an aptly nicknamed “Sinners Bible”; so named because an important word was left of of one of the 10 Commandments. I’ll leave it to those who care to look up what was omittted. A google seach on Sinners Bible will get you all the hits you need.