A Google My Business Help thread has a local SEO who is furious with Google that over 60 of his clients were suspended from Google My Business (the local maps listings) overnight because he manages all these clients in a single account.

A Local Search Forum thread sums it up well:

It is similar to having your spam accounts in one Google Search Console account. Don’t do it if you are spamming.

I honestly hate seeing this type of stuff where an SEO does something so dumb that all his clients suffer from it.

Forum discussion at Google My Business Help & Local Search Forum.