But the group of three smartly-dressed women, all from London and in their 20s, were caught after a keen-eyed CCTV operator spotted them swarming over 79-year-old Jean Ennis as she shopped in Wilkinson's, Southgate, Halifax.
The footage, which was screened to Bradford Crown Court by prosecutor Judith Naylor, clearly shows Elisaveta Mihaylova, 27, Elena Ilieva, 29 and Rumyana Ivanova, 25, following Mrs Ennis, of Halifax, into the shop before grouping behind her as she looked at towels.
The women held up bath mats to try to block the cameras as they rifled through Mrs Ennis's handbag while she continued unaware.
Mrs Ennis managed to walk away with nothing taken but she later realised her purse had been tipped on its side in her bag.
The women were detained in the shop and later arrested.
Judge Stephen Gullick, speaking as he sentenced Mihaylova, of Hewitt Road, Haringey, London, to 11 months in prison, said: "You were clearly part of a sophisticated well-oiled team who travelled to West Yorkshire targeting elderly people with a view of relieving them of their items.
"This lady was surrounded by three of you making clear and persistent efforts to take her purse.
"You knew perfectly well what you were doing and what you were part of."
Ken Green, for Mihaylova, who pleaded guilty to attempted theft, said: "She has been having a difficult time in custody. Her husband and children are in Bulgaria and she has had no contact with them for a long time."
Mihaylova, who has two previous convictions for the same offence and has already served 113 days in prison, screamed as she was taken to the cells.
Ilieva, of Turnpike Lane, Haringey, London, was jailed for 12 months, and Rumyana of Green Lanes, Haringey, London, was given 150 hours of unpaid work after both pleaded guilty to attempted theft at previous hearings.