we have to use banksman or as our firm calls them “reversing assistants” It helps if you have the same crew mine changes everyday at the moment so you cant build a bit of team work up my colleagues who do have a regular crew have it sussed as they know how each other operates I think its a good idea though as you cant rule out someone running from behind a parked car or agressive drivers and when you are in a busy town 3 or even 4 sets of eyes are better than 1