I’m only 12 weeks pregnant, and last time I used to carry a BOB badge and only put it on if I felt I needed a seat (e.g. a few times in the early days when I felt sick/faint). Later on sometimes people would notice the bump and offer anyway, or I’d just ask. I’ve noticed a lot of women on my commute wearing them the last few weeks only some with a noticeable bump, and a couple of times have happened to be sitting in the seat next to where they were standing so obviously offered my seat. However, is it selfish to wonder if everyone wearing a BOB badge needs a seat more than those who are PG without a badge? Would it be reasonable to assume that anyone wearing a badge genuinely needs a seat?