There's been quite a bit of fuss lately in the bra blogger world over Simply Yours' post where they told women to measure their bra band by adding 4" to the underbust measurement. What is particularly striking to me about this instance of this bad advice is that their fitting table actually acknowledges the existence of 23-24" ribcages- but it then goes on to say that someone with this measurement ought to wear a 28 band. It's clear that it will be impossible to convince manufacturers to make smaller bands until people realize that adding 4" is nearly always incorrect.
One of the best illustrations I have ever seen of just how bad it is to add inches is Georgina's video blog in which she tries on a 40G, the size she would wear if she added 5" to her underbust measurement. Really, just go watch it- and the when you're done, head on over to Simply Yours and tell them why they are giving women bad advice.
Also check out Cheryl from Invest in Your Chest's response here, the post on Busts 4 Justice here, and Sophia Jenner's response here.