i think it's mostly to do with our society... you know those aunties who'll tend to give you a kind of look when you do inappropriate stuff.... and perhaps just by looking you cant tell that ppl are wedded and such....
i experienced something like this too... sometime back when i got a pregnancy kit from a pharmacy and the ppl in the shop as well as the cashier gave me a one kind look which made me feel embarassed

heh heh
just like one time when my brother was telling me that he was standing outside a shop waiting for a friend and he saw a guy go into the shop to get a female magazine a few minutes later he went into the shop again to get a pack of condoms... on one hand open minded ppl might think "what's the big deal?" but on the other hand ppl will be speculating why do they need the condoms....
just based on the stuff i mentioned above will make some ppl self conscious when buying certain "taboo" stuff ...
heh heh just my humble opinions....