By the way, I know many well educated Johns and Pauls but if I'm honest, not so many Sharons and Janets. I think you're lumping two classless male names that have been used for centuries with two female names that attract more preconceived opinions.
Remember that tv programme called Ladette to Lady? They took badly behaved girls and tried, Pygmalion style, to mould them into well bred 'laydees.' There were a couple of double barrelled surnames among them. So it is pretty usual for some people to do it now.
If you're interested, their first names were: Sarah x 3, Jemma, Clare, Jessica, Michelle, April, Victoria, Rachael, Laura x 2, Louise, Frances, Clara, Simone, Amber, Kelly, Charlotte, Emily, Zoe, Maria, Bianca, Skye etc.
Not all of them are as stereotyped to background as one would think, are they? With the exception of the Australian ones (Bianca, Skye) some would expect the ladettes' group to have more Brittanys, Ashleighs and Keiras but after the early 90s, times have moved on and there has been much more harking back to grandparents' names.