Green’s Dictionary of Slang

(UK Und.) any means of gaining money through (excessive) politeness.

1821		W.T. Moncrieff Tom and Jerry II vi: We haven’t had a better job a long vile nor the shabby genteel lay. That, and the civil rig, told in a pretty penny.
1835		G. Kent Modern Flash Dict. 9: Civil rig – a trick of the beggars to obtain by over civility.
1848		Flash Dict. in Sinks of London Laid Open [as cit. 1835].