It's not flipping. Flipping is where Bob fully completes the purchase of a property from seller Alice, Bob pays the property transfer tax [0], Bob takes possession of the property as the new owner on the title, and then Bob re-lists his property on the market at a new price, ultimately completing the sale to Charlie.

What's happening here is that agents involved in the sale of Alice's property provide Alice with a price of (for example) $1M, which Alice accepts under the assumption that her agent is representing her interests fairly and objectively. After Alice accepts this price, the purchase is delayed. While Alice waits to receive $1M for the sale, Eve (another agent) is assigned the property and sells the assignment to Bob for $1.25M. Bob then sells his assignment to Charlie for $1.5M. Charlie then completes the purchase, and only then is the property transferred from Alice to Charlie. Charlie pays $1.5M, but Alice receives only $1M. Eve and Bob both profit $250K each, never having taken possession of the property themselves.

[0] The tax is charged at a rate of 1% for the first $200,000 and 2% for the portion of the fair market value that is greater than $200,000. Source: http://www2.gov.bc.ca/gov/content/taxes/property-taxes/prope...