Due the great number of variables involved with breaches of this policy we deal with each on a case by case basis. However, we have general guidelines that are usually followed in certain scenarios ...
If we discover (via our monitoring or other means) a spam attack (many spam emails being sent from our server) in the process of happening we will react immediately to stop the emails leaving our server by finding the account which is the source and suspending it straight away.
Following this, we will contact the client who owns the account to inform of the situation and why the account is suspended.
When we have gained contact with the client a suitable course of action is decided. Our priority throughout is stopping the spam from happening at the time and stopping it from happening in the future, so until we are sure this is the case, the account will remain suspended. In the majority of cases we are able to work out a solution very quickly after gaining contact with the client.
In some cases we do not become aware of spam problems until the complaints are received. An example of this being the case when the spam is sent from a server we do not control advertising a domain we host.
When we receive spam complaints we immediately contact the client who owns the account in question to inform of the complaint and gather their feedback. At this point, we do not suspend the account accused of spamming unless the circumstances are very serious (not often) and we await a reply from the owner before deciding on the course of action.
If we do not receive a reply from the account owner in a reasonable timeframe and the spam complaints continue to be received we may suspend the account to prevent our servers being listed in various spam prevention databases.
As already mentioned, there are many things to consider in cases like this which is why we do not have a 'hard and fast' set of rules. It should be noted that the above scenarios are very general and additional circumstances such as multiple separate spam problems are likely to be handled differently.