Re: Are na-mehram bra sellers ‘death’ too?
Only if they sell the bras wearing a black cloak and holding a scythe. 
This is just a guess on my part, but I don’t think that the na-mehram bra-seller would be considered “death” for women because they will not be interacting with him as frequently as they would with their brother-in-law. So, despite being na-mehram, he is not on the same level as the BIL. Even if one were to argue that bra-seller would know something as personal as your bra size…it’s still not an intimate interaction …it doesn’t require the effort to bond or firm a relationship whereas people do make the effort to bond/connect with in-laws. With the bra-seller, it would be a very cursory interaction…pick out your product, pay, and leave.