I fold mine all the time. I use just about every weekend and fold it up afterwards. Except for that picture I never use the tilt feature, it doesn't feel safe riding up then it slamming down. I'm big enough to lift it and fold it up by myself, its a PITA though. If I wasn't restricted on space I'd buy a bigger one in a heartbeat.
I don't know what I must have done wrong because it's too much to fold. I've used it several times now and I can't get the tongue to separate from the frame anymore. And I'd never leave it standing on it's casters that close to a vehicle. It seems like it would just fall over on its own. When I could stand it up I strapped it to the wall so it couldn't fall over in the garage. It's raining like mad right now and I left it outside today because I can't fold it and put it into the garage. It does tow well, but I wouldn't recommend one to someone who needs to be able to fold it.
Just pry apart the part that the tongue rest in. I had to do that when I first put it together.