There are no rules for the length of time for exercise, and as others say if she didn’t meet loads of people she’s not done anything wrong. My partner and I regularly go out for that length of time with the dog, there’s nothing else to do so going out for a long walk is very therapeutic.
She does plenty of dickheadish things to comment on without having a go at her for doing something she’s perfectly entitled to do
She does plenty of dickheadish things to comment on without having a go at her for doing something she’s perfectly entitled to do