I think that you could if your back wheel went into a skid if you were doing a decent speed. But i dont think it would jack-knife because there wouldnt be enough wieght in the trailor to be able to push the back end of the bike around.
But it says on them that they shouldnt go faster then 10mph, how boring is that. What happens if you go faster, and would they snake like a caravan?
A while back I had finished shopping in Sainsbury's and had a full load on my Bike Hod. I came out of a side street turning right across a busy city centre road when the trailer seperated from the bike right in the middle of the lane! I carmly lent the cycle on a lamp post, walked over to the trailer and calmly walked back with it to the cycle. Luckly enough it didn't tip over.
I had not put the locking pin through the attachment
Jack-knifing happens to lorries when the rear wheels of the towing vehicle lock up and the inertia of the trailer pushes the tractor unit from behind, forcing it sideways and around. A bicycle, being a single track vehicle (and assuming that there is enough weight in the trailer to overcome the weight of the rider) would tip over at approaching 90 degrees rather than jack-knife. A tricycle could be made to jack-knife given enough trailer weight and good enough rear brakes.
I used to tow a Cannondale Bugger (yes Bugger) which attached to the seat post. It wasnt unusual to have the weight of my drunken friend push the back wheel of my bike up in the air under hard braking, a kind of vertical jack-knife if you will.