I've taken my older brother into the Grand Canyon and my brother-in-law across the Canyon, neither had any experience. Both trips went well but only because a lot time was spent in preparation and discussion. My brother researched what he needed and that combined with what I told him he needed resulted in him being pretty well equipped.

My brother-in-law trained hard but brought little in the way of equipment other than clothing. I supplied most of that and, in the hopes of ensuring his success, limited his pack weight to 25 pounds.

I guess IMHO letting the newbie bring junk equipment is a recipe for disaster, unless your aim is to teach them a lesson and ruin your trip at the same time.

Heard many stories of people taking newbies like you're talking about and none of them turned out well. Saw a guy last week in the Winds dragging a pack on the ground that he obviously couldn't carry anymore. He was just about back to the TH when I saw him. Don't know how far he dragged it but I could see the trail left by it in the dirt continuing up main trail before I turned off.