Also surprised how angry people are on this thread, surely it is down to the individual if they wish to wear it or not.
I have a 90 minute commute each way on a very busy tube, and have worn mine since 12 weeks. More to stop people shoving me than anything.
I have found it seems to depend on what line and what area of London I am in, on whether people take any notice of the badge or not.
On the Jubilee line, it tends to be ignored. If I get on the District Line in West and Central London, I will always get offered a seat, yet if I get on the District line in East London I will never be offered a seat and still be quite aggressively shoved out the way by men and women.
I have also found that men are a lot more likely to offer me a seat than women, who seems to just glare at me and make me feel ultra uncomfortable.
I changed my hours slightly to try and avoid rush hour, but with all the Christmas shoppers this month, it hasn't really helped.