its more a sign that the advertiser is doing something to hide their identity: you can't id the user of one of those "secured" numbers by googling it and looking for hits
sometimes the advertiser does it because he/she has been suckered by Vivastreet into spending more money, but my experience is that usually when you see one of those numbers, there's a dodgy endgame
In this case, the advertiser has fucked up by putting a real number on the admin account, its quite a common error which has enabled me to ID rogues in the past. Sometimes though you'll see dumb Romanians who pay for a secured number - and then put their real number in the free text in the advert. I'm convinced that happens where Sergei places the original advert, and the girl then changes it
In the case of your friend Fran, she has a real phone number in the advert: 07397894320
My guess there is that she's ticked the wrong box in renewing the advert, got stuck with a secured number and doesn't know how to revert back.
