I can see where the Flexi would not be ideal for both dog or person in certain circumstances. I've seem many instances where users just can't figure them out, or are not good at using them and that is hazardous to all involved! However, I live in the country and find that the long 27' Flexi is a good way for her to burn energy on our walks where there are no people or cars around. If my dog sees a squirrel, deer, groundhog, etc. and dashes towards it as most Basenji's do, I anticipate it getting to the end of the lead and already have my arm in a back position and cushion the dog when it gets to the end by letting my arm go forward in a "shock absorber" fashion. Also, my dog has learned how long the lead is and will usually slow itself down when it knows the end of is near. IMHO, I see no harm in it if used properly and in the right areas and circumstances although one has to be very aware of what is going on around them. For where I live in the country, I don't see much sense in having my dog walk perfectly beside me. Basenji's like to run and sniff things out so I let them. It is her time to enjoy. Just my opinion.