Seems to me that stuttering around strangers and being more fluent amongst friends/family/people that you know well, is more common? I'm the opposite. The better I get to know people, the more likely I am to stutter with them. I kind of attribute it to, almost a sense of my brain not working as hard to make a good impression after I've known someone for a while. Then there's the 'in-person vs over the phone' thing. Im always far more fluent in person than over the phone.