@berto - I've been busy doing things out in the real world... here in the Pacific Northwest our summer lasts only a few days <sarcasm/> so I spend as much time outdoors as I can and no longer own a laptop so...
yes, bob-tailing can be dangerous...tractors are designed to pull trailers, typically the bulk of the stopping power comes from the trailers' brakes, this prevents skids/fish-tailing/havoc... however, it isnt such an issue anymore with newer tractors as they have superior braking systems now-a-days...