Note that Google has numerous methods of tracking your identity via your Google accounts and your IP addresses both at home and at work and we can assure you that it will eventually backfire if you violate any of their guidelines and could seriously harm your Google rankings.
Below are the most important guidelines which are commonly violated:
Conflict of interest: Reviews are most valuable when they are honest and unbiased. If you own or work at a place, please don’t review your own business or employer. Don’t offer or accept money, products, or services to write reviews for a business or to write negative reviews about a competitor. If you're a business owner, don't set up review stations or kiosks at your place of business just to ask for reviews written at your place of business.
Impersonation: Don’t post reviews on behalf of others or misrepresent your identity or connection with the place you’re reviewing.
Spam: Don’t spam. Write a genuine report of your experience with the place. Don't include promotional / commercial content, don't post the same content multiple times and don't write reviews for the same place from multiple accounts.
In summary, you should not have any problems if you encourage your customers and clients to provide you with honest reviews using their own Google accounts from their own computers.