Depends on the airport and its regulations, along with the handling firms equipment/policy... in all honesty i think a 1 man push-back is unsafe... say the tug driver suddenly took ill during pushback at a crucial stage, could lead to damage, injury or even death, but thats my views
BFS is a 3 man push-back, 1 for traffic / removal of bar / bypass pin, 1 tug driver, 1 on the headset... this is the same throughout the 3 handling firms (Aviance, Menzies and Servisair) this is similar at many airports that have roads at the back of stand