Backing in to parking spaces is standard clipboard warrior best practice stuff and has been for the past couple decades. It reduces backing accidents from a tiny number per huge number of man hours to a tinier number per huge number of man hours on average (not necessarily for a specific work flow, best practices are not a replacement for good judgement and evaluation of specific circumstances). It has nothing to do with the safety of a job site and has more to do with the size of the company that runs it (small companies don't tend to issue blanket policies for that kind of stuff).