Coincidentally this came up at our board meeting last night. It is continually a hot button issue for many buildings, and has an equal number of circumstance. It really depends on the what the infraction is and how often it has occured. Each instance must be recorded by the management company and followed up in writting to the offending resident. Without a paper trail there is NO chance of removing the person, and even when documented it is VERY difficult to get a judge to issue an eviction order. If the coop has the ability to issue monetary fines it should be done and pushed for collection. Even if they don't pay now you will collect it when they try to sell or sublease the apartment.
Be aware that unless you have shareholders willing to step up to the plate if it goes to court you are wasting your time, unless there are Police Reports. And, if it is one shareholder complaining about another you also are going to have a difficult time taking legal actions.

As you can see it is a complicated issue and is really a question to best answered by the coop's attorney.