Hi, My pure breed Border Collie is EXACTLY the same. I have had 5 Border Collies since a kid & the last two have been like this. I actually don't discourage his behavior towards strangers because one day I might need him if the wrong kind of stranger approaches me! I just control the situation & calm him down accordingly. He is 6 months old now & has started going crazy at Skateboards & Cyclists so I am now training him not to with a lot of patience & we are making progress. I see this post is older now. How are you getting on?