Salesmen "travelling in ladies' underwear" have traditionally been considered snigger-worthy; men who hang around lingerie departments even more so. Knickers and vicars are the stock-in-trade of British comedy. Take this scene from Father Ted, in which a party of Catholic priests accidentally find themselves thwarted by thongs:

As so often happens, what is pervy to Westerners is normal in Saudi Arabia. From the BBC, with thanks to Alan:
It would be bizarre in any country to find that its lingerie shops are staffed entirely by men.
But in Saudi Arabia - an ultra-conservative nation where unmarried men and women cannot even be alone in a room together if they are not related - it is strange in the extreme.
Women, forced to negotiate their most intimate of purchases with male strangers, call the situation appalling and are demanding the system be changed.
[...]
Rana Jad is a 20-year-old student at Dar al-Hikma Women's College, and one of Reem Asaad's pupils and campaign supporters.
"Girls don't feel very comfortable when males are selling them lingerie, telling them what size they need, and saying 'I think this is small on you, I think this is large on you'," she says.
"He's totally checking the girls out! It's just not appropriate, especially here in our culture."
"Totally checking the girls out"? What's with the Valley Speak?
The situation is all the more frustrating because the relevant legislation is already in place.
In 2006, the Saudi government passed a law stating that women should be allowed to staff any shops that sell women's items, be it clothing, accessories or underwear.
But the law has still not been properly implemented.
No official reason is given for this, but one probable cause is that hiring female staff would put a lot of men out of work - not a popular move in a country where 13% of men are unemployed.
There are also Saudi Arabia's Muslim clerics to contend with.
They wield a great deal of power in the kingdom and still believe a woman's natural environment is in the home.
I wonder if the salesmen sample the products. I have a feeling - just a hunch - that many Saudi men wear a bustier beneath the bisht.