Hi-just wanted to add in on this one. Sort of in the middle of both of those comments.
Actually, I totally agree with Pearly, but the reality is that when you're in a country park or something there are so many people that are clueless or just don't see the point of view of dogs and that they are not little humans, that you do have to plan for the inevitable.
My dog was two in July. She has been heavily socialised in big open spaces withth all sorts of breeds twice a day-off lead since 11 weeks. She has been nipped, bashed, pinned down, rolled over-all sorts. She's always been fine around other dogs.
Earlier on this year she was in a down stay while I threw a ball in to a copse for her to find. A friendly (but bonkers) cockerpoo came bounding through into the area, saw Inca and jumped on her. It sounded like my dog was going to kill her!!! The owner was a bit taken back but like pearly said-fair play. If someone came and jumped on your head while you were waiting for a bus would you think you had to be polite with that person??
I'm not sure if it was triggered by that event but ever since, my dog will definitely assert herself more and she does have a right go sometimes. Funnily enough, every time she sees that dog now, she'll have a go at it to start with. I just acknowledge her opinion and then it's fine after that and they will actually play nicely together, but Inca definitely says 'Just before we start, don't even think about jumping on me ok or I'll have you?' And once that's cleared up, everything is fine.
We have had a few issues with guarding tennis balls too-she would be nasty over that (again, would you think it was ok for someone to come along and want to play with your handbag?) but that has moderated a lot. I don't bring the big guns out where there are other dogs-I use less valuable balls and my dog is told to leave other dogs balls alone. I did sometimes carry a secret tennis ball in case mine did get someone else's then she could have hers as reward for dropping the stolen one but she's much better at leaving now.
I did worry when I first saw this behaviour but I concluded:
-Dogs only have limited communication tools, so if they are really unhappy, they've only got barking, snapping etc to show their displeasure. It nearly always sounds much worse than it is. (My dog has never actually nipped another dog).
-Try not to worry about it too much. Just look at the situation-call your dog to you if you need to, or go and get it. Often just you calmly saying ok we get the message-that's enough will be enough to diffuse the situation.
- Your dog will feel threatened if it is on the lead and the other is not, so personally, if it's a safe place,I'd let yours off to greet the other dog naturally. (Also that will prevent your dog practicing being reactive). However, If you don't want to and the other dog comes bowling up in a rude way then the owner should expect that yours might react! It's an obvious possibility.
If I see a dog approaching on a lead and mine is already off, I might call ahead just to check it's not dangerous but I don't worry as I can call mine back and more importantly, I know exactly how my dog will behave when greeting a strange dog. She will trot towards it and then lie down at a distance. Once the other dog has had a chance to assess her she will slink towards it very low to the ground and 9/10 lie on her back. This is polite behaviour and should be fine with all but the grumpiest of dogs. Never the less, if mine does decide to approach one on a lead it is still her risk to take and I wouldn't take offence if she did get snapped at, but that's why I check ahead to avoid that.
I don't think there are many pet dogs that start a fight for no reason and largely they are capable of sorting out their own issues-always best off lead with the option to get away if they feel the need. They don't mind being told they're not the boss-It's the humans putting their own ideas in that confuses things.
I'm sure yours is fine. Don't stress him further by keeping him on the lead more- I think that will make it worse. I would give him enough freedom and space to talk dog with the others and I'm sure it will settle down.