Here's an interesting blog about the needs of men who wear bras. In the light of this thread and how it has gone though, the most remarkable statement is this:
Sadly, not all of our customers are comfortable with the idea of being fitted and trying on bras next door to a man doing the same thing, and none of us would want any of our customers, male or female, to feel uncomfortable with the process.
Now I realise the situation described is a little different from what we've been discussing, but here is a simple acknowledgement that not all women are comfortable if men are near in this situation. No judgement. It's simply the truth. A statement of fact:
You may be fine, I'm not.
The bra fitter therefore suggests that men should phone ahead and ask about the best way to organise a fitting. She does this not only because men who wear bras often feel uncomfortable in this situation too, but also because the default customer and fitter arrangement is female-female.
And anything that deviates from that expected norm could make people uncomfortable, a situation no store wants to find its customers in.
I do therefore find it entirely appropriate if someone has concerns in this area, to contact the store and share these concerns. Why not? Our feedback is sought by stores constantly, every single time I get a receipt I'm told to go to this webadress or that survey and tell them how my shopping experience was.
As it happens I couldn't go to the other branch to buy a bra today, had to hit my local branch instead. Since our changing rooms are now shared between men and women, two shop assistants were there supervising (normally there's no one there). So it did feel very safe if uncomfortable being half naked in a space that was single-sex before. But because the cubicles only have curtains and there were a lot of male customers, there was just no way I could ask for a fitting.