If you see another dog on-lead, and your dog has a poor recall - get yours on-lead too - allowing an offlead dog to approach an on-lead dog is at best bad manners and at worst downright dangerous. I don't blame the guy for trying to defend his pup. Whenever I go to the park with my friend and her dog-aggressive JRT, it never ceases to amaze me how many owners allow their dogs to run over and harass the JRT despite her being on-lead and muzzled, stressing her out even further! x