What is the necessity that the dog be off lead? It will still get exercise when it is on lead on the walk. Even with my off lead reliable dogs, I leash them when we are in high traffic areas. Even if your dog is reliable, that does not necessarily mean that external distractions will not pose a threat and cause a liability. In addition, there are lots of people that are scared of large, guard dog breeds - no reason to subject them to a large loose dog. You might know she is friendly, but that does mean everyone else will be comfortable with a loose GSD. There is widespread bias against certain breeds (rotts, pits, dobies, mastiff breeds, GSDs etc). If I have my little Golden Ret. fluffy mix off lead next to me, most people just find it cute and hardly anyone will react negatively to her. If I have my large serious male GSD next to me off lead, I will get a different reaction so that's something to take into consideration. Many insurances have limitations or biases against GSDs and certain breeds. What will insurance say if something happens - also something to look into.