My Asia has the same dislike of terriors, Akita's do seem to have very long memories and my Asia will remember a certain garden or place where another dog has had a "pop" at her, when she passes that same garden or other place she will always make sure she has a very hard look around, I know she's looking for the dog that had a go at her. I and many others have problems with terriors, they do seem to take a dislike to akitas. The last incedent I had with 2 shitzues (spelling) was when they were both off lead and came straight for her, the owner was out of sight and when he did turn up he said that his dogs were very aggressive, so why the flipping heck did he have them off lead!!!
anyway as one of the dogs was hanging off Asia she had a pop back at it, I could do nothing, it was a lot of noise and everything ended okay, but I had to avoid the area for ages so that Asia could stop getting "huffy and puffy", she's okay now
Personally I always cross the road if I see any other dogs coming, even if it's a dog that Asia gets on okay with. A little trick you could try is to give Niko a treat when you see a terrior aproaching, hold the treat just in front of his nose as you continue to walk and once you've passed the other dog let him have the treat, don't let him look back at the dog either, Asia's a proper one for doing that
In time Niko will learn that he gets treats when another dog is around and he'll start to look at you for his treat instead of eyeballing the other dog.
Personally I don't think his behaviour warrents a muzzle, if people see him muzzled they can become complacement and get too close ot him, he'll proberly feel more defensive if he's muzzled and he could get a reputation simply because he's wearing a muzzle. As long as he's on a lead at all times you are seen as the one who's dog in under control the off lead owner is the one who's out of order
