Are the vacations genuine?

Absolutely genuine.  Resorts as well as marketing companies have been selling similar vacation packages for 25 years and generally selling them at much higher prices.  Nearly all hotels, resorts, cruise lines, etc. have vacancies on an ongoing basis.  They find that participating in Vacation Package programs is a viable form of advertising to bring in guests who obviously then spend money in their restaurants, bars, shops, etc.  Today many savvy travelers use promotional packages such as this for their vacations, saving thousands of dollars each year.