1> The adventures of Sherlock Holmes are works of fiction. 2> I think the Baker Street Irregulars were homeless street urchins and did not have any choice but to roam the streets.

Conan Doyle wrote in this group of kids exactly because, at the time, it was a realistic and familiar sight to urban readers. There are lots of newspaper articles from back then (and if i remember correctly, even lots of Parliamentary tirades) about them. Over a certain size, they had become a matter of public order.

More recently, I remember Dublin city centre in 1988, when Ireland was still pretty poor, being full of kids; and Marrakech or Fes in Morocco just 10 years ago.