I've seen a lot of dogs on my rides. For the incoming people they normally see me and leash thier dogs right away. It's the people I come up fromthier six that some don't leash up. Sometimes ringing the bell well in advance does not help as the owner has his ears plugged with headphones. Tho normally I do ring the bell in advance so the owner at least has a chance to get thier dog and I slow down a lot in case the owner can't get tot he dog fast enough so I can pass slowly. Most dogs I've seen will go to thier owner if called which is good. I've had the occasional dog that just would not listen to thier owner but thankfully it's wagging it's tail all friendly coming up and smiffing the bike.

I wonder, if you attach a dog whistle to the front fork if you'll have a dog army following you so no one messes with you on your riding warpath.