Shoplifting is supposed to be a bit exploitable, at a risk. Obviously some people are going to be better at it than others, so maybe the chances of being noticed and caught could be tied to one's Stealth stat, and the risk of being identified and banned from a store permanently tied to one's Disguise stat? The deterrents to stop people from abusing the mechanic too much would already be in place (it's a crime, obviously).
I can imagine Mixers taking the mag-lev up to malls on Gold or Green, trying to make it away from stores with luxury goods that they could then fence (re-sell) through a Fixer. Wanted posters (complete with grainy/blurry photos) hung up at stores for repeat offenders. Security guards chasing Mixers with stolen goods through crowded malls. Wearing poor disguises that make you less likely to be recognized in the event that you're caught and forced to run... but more noticable when you're actually in the act. Merchants down in Red hawking makeshift security tag removal guns. Et-cetera.