▁shop l ifting , ▁including ▁storing ▁small , ▁expensive ▁items ▁in ▁locked ▁glass ▁cases ; ▁chain ing ▁or ▁otherwise ▁att aching ▁items ▁to ▁sh el ves ▁or ▁clothes ▁ra cks ▁( part icular ly ▁expensive ▁items ); ▁att aching ▁magnetic ▁or ▁radio ▁sens ors ▁or ▁dy ep acks ▁to ▁items ; ▁installing ▁cur ved ▁mirror s ▁mounted ▁above ▁sh el ves ▁or ▁video ▁cam eras ▁and ▁video ▁mon itors , ▁h iring ▁plain cl oth es ▁" store ▁detect ives " ▁and ▁security ▁gu ards , ▁and ▁b anning ▁the ▁bringing ▁in ▁of ▁back pack s ▁or ▁other ▁b ags . ▁Some ▁stores ▁have ▁security ▁gu ards ▁at ▁the ▁exit , ▁who ▁search ▁back pack s ▁and ▁b ags ▁and ▁check ▁rece i pts . ▁St ores ▁also ▁combat ▁shop l ifting ▁by ▁training ▁employees ▁how ▁to ▁detect ▁potential ▁shop l if ters . ▁ ▁The ▁first ▁documented ▁shop l ifting ▁started ▁to ▁take ▁place ▁in ▁ 1 6 th ▁century ▁London . ▁By ▁the ▁early ▁ 1 9 th ▁century , ▁shop l ifting ▁was ▁believed ▁to ▁be ▁primarily ▁a ▁female ▁activity . ▁In ▁the ▁ 1 9 6 0 s , ▁shop l ifting ▁began ▁to ▁be ▁re defined ▁again , ▁this ▁time ▁as ▁a ▁political ▁act . ▁Research ers ▁divide ▁shop l if ters ▁into ▁two ▁categories : ▁" boost ers " ▁( prof ession als ▁who ▁res ell ▁what ▁they ▁ste al ), ▁and ▁" sn itch es " ▁( am ateurs ▁who ▁ste al ▁for ▁their ▁personal ▁use