I am currently also a dog walker with Wag! And of course I take care of my own doggos. I have experience with all types of situation when out and about with a dog. I have personally had an aggressive dog run up to my own dog and was able to successfully navigate my way through the situation. I make sure to bring a spray bottle with fan (to keep the dog cool) , water , poop bags and of course treats on all walks. If your dog loves to run then I am more then willing to run with them. At the same time my own doggo is an old guy so I can also walk and let your dog enjoy the great outdoors.