You shouldn't feel that you need to buy anything specifically for clients, but I read the OP as saying that she was either advertising as having FFNs or when someone asked she said "yes, I can wear those", in which case fair enough.
People who are into them can get very enthusiastic (I don't know if SHQ still has a message board, but I always felt uncomfortable when I had a look at the fanatics reinforcing each other), but most men have no idea what they are, so no need to have them in your wardrobe if you're not into the idea yourself.
By the way, they don't have holes for suspenders. There's a single loop which is a result of how they're made. Also, the foot is always reinforced.
(http://www.voluptua-uk.com/catalog/images/FFNBlackPoint169x240.jpg)