Is it acceptable for someone to operate a MEWP from the ground controls with a passenger in the platform?

This is NOT usually allowed as the operator will be unable to judge distances from objects whilst on the ground. However, under certain circumstances and in accordance with a thorough risk assessment, it might be justifiable. An example is that of a cameraman at an event in a position away from all aerial hazards, all possible safety measures having been taken such as briefing the passenger about the emergency lowering controls and having the operator close to hand at the chassis.