Make the puppy come to you. While he’s on his way to you, still wearing the leash and collar, back up a few paces and then reward him when he gets to you. Continue the progression until your puppy, upon hearing the cue noise, comes to you and walks with you a few paces. Remember that puppies have a short attention span, so keep your sessions short, and end them when your puppy is still eager to do more, not when he’s mentally exhausted.
In Delaware, dogs are not allowed to run at large unless in situations when the owner is present and has control over the pet. An exception is for farm dogs. Also, during the night dogs must be kept in an enclosure from which they cannot escape, firmly secured with a collar or chain or other device, so they cannot stray from the premises, or are under the reasonable control of the owner or custodian. If an owner does not respect these laws and if the dog bites someone, the owner is subject to civil liability and for fines of up to $1,500.
You want to reinforce behavior you like, such as when your dog looks at but does not react to another dog a good distance away. If you have to stop an incoming assault from an off-leash dog, you can yell “SIT!” at the oncoming dog (sometimes it works) and then throw your meat treat on the ground near that dog and do a quick, calm U-turn and move away. Could the dog have some sort of meat allergy? Possibly. That’s just one more reason the dog’s owner should obey the leash laws.