Would you expose a coworker if you saw them stealing from the company?

I'd probably just kick back and try to notice a pattern and figure out a way to out them next time they stole-to totally embarrass them, to make them have to face what they were doing and not be able to get out of it. Just flat out tattling isn't really cool and sometimes it backfires so I wouldn't do that, I'd rather set them up (provided they are stealing on a regular basis or causing the company trouble by what they are doing). If they only did it one time, I doubt I'd say anything unless they were a real jerk and/or our jobs were in jeopardy.

If I didn't like the co-worker and I knew they would really get in trouble for it, hell yeah!

This situation depends.
It depends upon the item being stolen, if I think it is deliberate and if I have a good rapport with the person.

If it is someone I like, I will tell them:
"Be sure that stays here...You don't want the boss to catch you."

Most of the time they say "Thanks." I forgot I had that. Other times I have been given a smile and they put it back. For those I like I act like a friend, telling them, like a friend, don't let the boss see it.

If it is someone I have had problems with, I keep my head down and keep my mouth shut, unless it is something big.

If it is someone I truly despise, I try to avoid contact. If that doesn't work, I will get involved. I will ask them to put it back. Sometimes it doesn't work

Here's a story related to this:
My previous place of employment, I worked with a rude, hateful, annoying person. She was someone who worked entirely on instinct and it seemed as though she never thought anything out.
She was intensely jealous of me because I was interviewed for her position and hired to a position higher than hers. She hated being my assistant and was rapidly transferred to another group after she and a coworker in my group were known to be having a romantic affair. This person was nasty, conniving and used any means at her disposal to get the better of someone. One of her favorites was to write up safety violations on people who crossed her. She let the power of the Laboratory Safety Committee go to her head and her power trip caused her to burn many bridges in over 1/2 of the company. Many people were angry with her and were looking for any excuse to get her terminated.
One day a 3 year old digital camera was missing from a locked cabinet in a lab. She was one of four people with the keys. When they could not find the camera after two months, a new camera was bought. About two months after, she wanted to sell a Television Set and she emailed everyone with the picture. One of the co-workers who got written up on a violation and had quite a grudge, because it cost him a portion of his raise, decided to check the pictures. Most digital cameras tag the pictures with the camera brand, make model and the year of the camera. All these matched the camera which was stolen exactly. The odds of finding a similar camera in a pawn shop were slim to nil. It cost her her job.

It really doesn't pay to alienate half of a company. If you are going to do that, then expect that you will have half of the company looking for any excuse to have you fired. At least don't have the gumption to steal a very expensive digital camera.

If it is small stuff like a pen or two, then I don't get annoyed. I sometimes end up with a pen in my pockets after I get home. I give my best effort to return with it the next day, most of the time I do.

I was never stealing.
If I would see someone stealing I would do no report. I do not want be in trouble for company that is stealing from me. It is not my business.

If they made a habit of it i'd get video of them doing it so i could blackmail them.

Depends on the company in question. If it was an upstanding business, then I wouldn't hesitate to report the thief.... But if it was a company with an evil reputation who gets away with filing little to no taxes in the nation of employment, then I'd likely be encouraging such an action.

Confront the coworker, give them a chance to fess up. If they don't, they appear habitually dishonest, and it's only fair to tell your employers. If you don't see it quite that way, consider this: that profit their stealing is money that could otherwise help contribute to YOUR paycheck.

This is why its so effn hard to get a job now, no one is trustworthy anymore

i would only tell because someone who reports something at my job could get up to $5,000 for a reward. no joke. unless if i'm friends with the guy, i'd make him split it with me :)

No, the company deserves it. I sometimes steal too.

HAHAHAH YEEES. Eff you profit driven America.

nope I'd join in...

If someone steals something from the company it casts suspicion on everyone who works there, including yourself and your work friends. If you caught them in the act or can prove they took it, you would save everyone a lot of hassle and stress by doing the right think and telling the boss.

This is why I prefer self employment. As a business owner, I would prefer to hire trustworthy people. What I can afford or not afford to have taken, is none of their concern. They have their rules and their terms of employment. But, would I snitch to the boss about someone? I have in the past b/c the person's activities could have unfairly implicated me. So that would be my answer: anytime someone's idiotic behavior adversely effects me, they are going down in a heart beat.

It sure makes it easier to report them if they are really unpleasant to be around. I think I'd confront them first and find out what's going on, maybe I could help them.