Yes you have every reason to be cautious. There's just too many bad people in the world today. I will probably teach a hand signal to Mud so that I may use it if need be in a sitauation other than just playing. When I walk in a public place with lots of people, I'm always with a buddy and their dog(s), never alone.
In my experience, it does take a bit longer for them to catch on when the command is relatively long. For this reason I would suggest teaching a hand signal first, then later incorporating the vocal cue. The more you practice using the two together, they'll catch on and understand the vocal cue as well. =) It depends on the dog, though. Some of them have no trouble with wordy commands, and some have trouble focusing on the whole sentence and pairing it with the behavior.
Fortunately, I haven't had any problems with wierd people in my neighborhood. I live in the country, but I still have several neighbors, all of whom are too lazy to go outside and walk all the way out to the field and then walk more there. Lol. If anyone tried to do anything though, I know Rusty would defend me with no hesitation. He's very protective of me and seems to be an uncanny judge of character. Of course, he would never attack anyone that he simply just didn't like. However, if someone tried to hurt me, he would protect me. Most people think he's scary looking anyway. If they only knew he's a big old teddy bear. ^^ Mudflap on the other hand...I have no idea how she'd react. She's a big old softy and quite timid, but she has become very defensive before when an aggressive dog started barking and growling at me. And Zeke's always been very clingy and protective of me. So....I think between the boys and Mudflap the attacker would have their hands full. :dogsmile: