This is what happened in a Diet Pepsi Contest trial I saw talked about on Oprah. These two co-workers worked in an office, different shifts, but sharing a communal refrigerator in the office kitchen.
Co-worker A
always drinks Diet Pepsi. It was a well known fact in the office as she always leaves a can in the fridge. No one ever takes them as they all know it's her cans. (Nice office.

)
Co-worker B doesn't drink any kind of Pepsi, also well known in the office.
Pepsi was having some promotion where you might open the can that pops up a winning tab for one million dollars, or other tabs for lesser prizes.
Co-worker A leaves her shift, not drinking her one can of Pepsi in the fridge. Has done that before. Can is always there in the morning as everyone knows it's her can.
Co-worker B comes on shift, opens the can of Pepsi, finds out the can is the $1Mill winner, and starts shouting it off to the other co-workers that she's won a million dollars.
Next day, Co-worker A comes to work, is told, "Hey did you hear, B won a million dollars last night. She opened a can of Pepsi & won." Curious, she goes to the fridge to see if she's won anything in her can and finds her can GONE!
She doesn't need Sherlock Holmes to know Co-worker B stole her can. She would never have opened it, if there wasn't a Pepsi promotion.

She takes B to court.
Co-worker B claims that A left a can in the fridge, she assumed A didn't want it anymore and she took it to drink.
The courts ruled with Co-worker A - it was always
her can. Well established pattern by both co-workers.
While I agree with the courts, B could have walked away with a million dollars had she just kept her mouth shut after she had won, & simply sneaked off with the can undetected.