Jade Wang from the Google Maps Quality Team posted a thread in the Google Business Help forums with safety tips on how to protect your Google Maps listing for accuracy and ranking purposes.
The tips include:
- Verify your listing with Google so you can own it and keep it updated
- Be careful when hiring a third-party company to manage your maps listings
- Don't fall for SEO companies that claim they are Google and can improve your Google Maps ranking for a fee
- Never share your Google Maps pin number with someone else
- Do not "loan" out your maps listing to someone else
- Follow the guidelines
- Report any issues quickly over here
Some violations they've seen by third-party companies include creating multiple listings at fake locations or mail receiving agencies and hiring unrelated individuals to receive postcards at incorrect locations. Loaning out maps listings, asking for your PIN numbers, and so forth.
Forum discussion at Google Business Help.