I wonder if the business owner is aware that it goes against Google's and Google My Business policies to offer a discount towards their services in return for a 5 star review on Google?

I'm sure the business owner is, as I was not asked for a five star review, I was asked for an honest review.

Thank You Sarah, It is true, we ask for reviews from all of our customers. We don't specify any particular site and we definitely look for truthfulness in all our reviews. At no point do we, or have we, given a discount for a "good" review. Honest reviews help build a better company and a better customer experience.