Google has added one line to its Google My Business guidelines around co-working spaces. In short, if your business is out of a co-working space it must have signage, accept customers and be staffed to be eligible to have a Google My Business listing with a co-working address.
This was added to these guidelines:
"Businesses can't list an office at a co-working space unless that office maintains clear signage, receives customers at the location during business hours, and is staffed during business hours by your business staff."
As you can see, Google specifically has three rules for co-working spaces to be eligible to have a Google My Business Listing:
(1) Signage that is clear and visible of the business name.
(2) The business needs to be able to accept customers at that location during business hours.
(3) The business must be staffed during business hours.
Joy Hawkins wrote this up in more detail but I think this was first spotted by @StefanSomborac.
Forum discussion at Twitter.