I've only had someone correct one of my dogs twice. I used to groom a Toller for this lady and she used much different training methods than I do. Dance jumped up on her (which is rude, I know, but too many people encourage it from her and despite my best efforts, without others' cooperation, she still jumps up occassionally and I've kind of given up on getting her not to). Before I got a chance to get the word "off" out of my mouth, the lady squeezed Dance's feet hard and pushed her (pretty hard) off. I could have been proactive and not had Dance around, but usually Dance doesn't like people anyway so the last thing I was expecting was for Dance to jump up to say hello. She generally only says hello to friends that she's had a chance to get to know.
The other time was when I was visiting someone and it was busy, other people were there, we were all out in the yard, Tango barked at something she heard, and got a stool thrown toward her from somebody. Not with intent to hit her, but still, I was upset about it.
Other than that, nobody's ever tried correcting my dogs before that I can think of. My biggest problem is that guests won't respect my expectations of my dogs' manners. So if I tell my dogs to go away or get out of somebody's space, the guest is like "no, no, it's ok! I don't mind!". Which is really annoying. Or I'll tell one of the dogs to get off and the guest is over there like "get down, get down, listen to your mom" in this annoying babying voice. It's frustrating. Half the time I just put my dogs away when people come over, but then I get to hear "oh, those poor dogs" the whole time. So yeah, sometimes I wish I had dog savvy guests who would just tell my dogs to get off or go away otherwise it feels like that's all I do (the Dobermans are really rude about getting into guests' spaces because they're obsessed with being touched). I guess it's nice that I don't tend to have issues with people correcting my dogs, but having other people around my dogs can still be frustrating.