I don't quite see how Innovation Brewing would ever be confused as Innovation Brew Works. Can guys with a JD comment on that?
I'm trying to stay away from this thread, but...
I don't think it requires a law degree to come up with arguments around this. You need the lawyers to cite case law and precedent, but anyone can argue.
If you wanted to argue it, from either side, it's as easy as pointing out that to a customer unfamiliar with the specifics of either one of those companies, a google search could wind up on the other and be confusing. Thus, lost business due to the other company using your trademarked name. Intentional or not, they are confusing your customers and poaching your business (or simply causing you to lose business, in the event the two companies produce different products). Protecting your trademark eliminates the confusion and protects your customer base.
If you google a 6, you're not likely to get a 9. But if you're drinking and enjoying #9 your judgement is questionable to begin with, IMO.