. Doing it with a passenger in the cockpit might be even worse. If you know what you're doing and you having a knowledgable person in the cockpit (not necessarily a licensed pilot), you should be OK.
I've handstarted with no-one in the cockpit of our Jodel DR1050, and I'm happy to do so with a pilot or engineer
familiar with the type at the controls, but NEVER would I start with a passenger inside.
I got a scare when senior airline engineer offered to sit in and keep the engine running until I got in. He thought the throttle operated in reverse, and initially froze when the plane jumped the chocks at full throttle.