I had a trailer aeons ago.... It was the greatest thing! I dragged SKnot everywhere in it. It had room for 2 kids, so it carried SKnot and a giant teddy bear (complete with yogurt-tub helmet tied on with string. rule was you can't ride in the trailer without a helmet!)

I'm sure things have changed, but back then the trailer "hitched" to the seat post of my bike. If I were to fall over, the trailer would go over too. Couldn't lie the bike down on the ground or the trailer would flip. Kind of a hassle. I'm guessing someone solved that issue by now.