“I think it’s important to point out that the היתר of בעלה בעיר does not apply in the case of לבו גס בה, which may well include a next door neighbor or a boarder.”
Thank you for pointing that out. I was wondering about that. I am pretty sure that I know people who relied on that heter for a boarder. On the other hand, I know people who were extra careful about yichud when I lived by them for that reason. I am guessing that it’s more complicated when the issue involves a single girl as opposed to a married lady and a teenage boy.