TODAY | August 28, 2013
>>> a young woman that decided to take matters into her own hands when a thief stole her very expensive bicycle but her story comes with a strong warning from the police.
>> reporter: call it sweet revenge , though some might call it vigilante justice. 33-year-old kayla smith never imagined herself a vindictive type but that was before her brand new bike was stolen.
>> i asked for karma to run him over with a flat bed truck. i was angry.
>> reporter: she was more than upset. it happened here at the olympic village last week. smith locked up her bike worth more than $1,000 and went to visit a friend. when she returned, her bike had vanished.
>> i was like i'm a good person, why would somebody do this to me?
>> reporter: within 24 hours someone told her about an ad on craigslist listing a similar bike for $300. she wanted her bike back badly and decided to set up a sting of her own, arranging to meet the seller at a local mcdonald's parking lot. she told the seller she needed a test drive.
>> he was actually like well, yeah, don't ride away. and i was like don't worry, i won't.
>> reporter: she hopped on and started pedaling and never looked back.
>> i was feeling like an nfl that just scored a touchdown. i was like yeah.
>> reporter: with bike threat on the rise some may think don't get mad get even policy is a good idea but authorities warn against it. vancouver police caution setting up a meeting with the person on your own can potentially be very dangerous. you do not know who you are meeting, how many people will be there, and how desperate that person maybe.
>> sometimes you just need to stick up for what's right and what's yours.
>> reporter: the thief still hasn't been caught but smith has her bicycle and her sweet revenge , even if it was, as police say, a very bad idea. for today, nbc news, chicago.
>> what have we learned.
>> you make sure it's your own bike you're taking first of all.
>> how did she know for a fact.
>> i know my bike. if someone stole my bike i would know it.
>> i'm not sure getting your bike back is worth what could have happened if that