full name: La Linea de la Concepción. Years ago, during Franco's time, there were Smugglers and lots of smuggling going on there. But now that you can buy fake Rolexes and 'knock off' Gucci handbags all over, la Linea has probably lost its pre-eminence as a smugglers Paradise.
It's not too far from Valderrama Club de Golf (San Roque), so maybe its seedy reputation has been displaced