Nissan has been providing rear view mirrors (RVM) on sit down riders as standard for many years. And RVMs are commonly found as standard on forklifts built for the Asian markets.
Most other forklift companies (in the US) offer rear view mirrors (some L & R side or center mounted, too) as a standard price book option or as a non-price book listed option.
For certain, if they presented a liability issue in the US one of those "ambulance chasers" from Philadelphia would be on it in a New York minute or faster than a lift truck sales person on a new customer request for quotation.

PS: Nothing against anybody from the Northeast just recalled a couple fitting phases. I have some good friends and acquaintances from these areas. But just can't get used to those New Jersey Cup Handle left turns. For a first time visitor, like I was when I drove 5 miles before I figured how to make a left turn (in New Jersey time 5 miles equals 37 minutes). Overhanging trees covered most the Cup Handle signs. Maybe NJ will get them trimmed with some of Mr. "O" 's stimulus $$ by classifying the need as a "shovel ready" project.