I've recently been trying to take my border collie out more to get her socialized and to get used to being in new places. I took her to a local dog park and usually she's nervous at first but then after a while she will get a little better. She usually doesn't have any problems with the other dogs- she usually just rolls on her back when new dogs greet her. At most the only "issue" is that after a while of being at the park, when dogs are running around she'll start trying to herd them.
However, the other day I took her and there were only two other dogs there at the time but they left shortly after we got there and then my friend met me there with her dog who my dog is fine with. After that though, someone came in with her two leonberger dogs (which are massive dogs) and I guess my dog didn't know what to make of them since she hadn't seen dogs of that size before. I was standing with my dog, my friend and her dog, and the owner of the two leonbergers (her dogs had wandered to the back), but then they started to walk up to us and my BC started to growl and bark if they got to close to us (even the owner of those dogs). I had her follow me away from them but anytime they came close she would do the same thing. At one point she started acting more protective (I'm assuming) even though the dogs were so mellow and well behaved.
I put my dog on her leash because I was thinking it would just be better to leave or even to just keep her on the leash and away from the dogs until she calmed down a bit but then other people were telling me that leashing her would make it worse so I took the leash off and was going to give it a few more minutes to see before I left. Eventually we got her to realize they weren't a threat and she stopped barking at them. But is it wrong if I had kept her on the leash? (Not for the whole rest of the time and not around the other dogs) I didn't want her bothering the other dogs but I don't know how else to have corrected her. She's 1.5 years old and unfortunately still learning.