I know it sounds like a bad idea when you say it out loud, but I don’t think it’s that crazy. Bike racks are fairly simple devices. All they need to do is not fall apart. This rack seems to be built fine, welds are good, all the nuts are locking nuts, there are several cotter pins involved.
My main concern is how the bike goes onto the rack, since it’s a long cargo bike. Can’t just do the top tube, that would be horribly unbalanced. It looks pretty good going through the rear rack. This is a RadWagon 1 so it has a steel frame (steel is real) so I think it will be fine supporting the weight of the bike. It doesn’t line up with the current mounts on the rack, but I’m 3d printing a solution that should be ready to take the bike to my great Aunt’s house this weekend.
On my 15 mile test run last night things seemed ok. Got up to 65mph on the highway once and you can definitely feel it back there, but it didn't seem like it was going to fall off.
Overall I think it’s a good rack. It’s rated for 100lbs which I’m well under at 68ish. Bike from factory is 75lbs, minus the 7lbs battery and the running boards means it’s not that heavy of a bike. A lot of people recommend the wheel mounted racks for ebikes, but the ones that are cheap enough have low weight ratings, and I can’t justify spending $400 on a bike rack, that’s like more than half the cost of the bike. I’m no stranger to trailers, or mounting things to my cars, I feel like this is a safe setup.