Hi,
If I understand, you're talking about publication conflicts. In that case, Service studio have a powerful merge, were you can decide in all conflicts what code prevails.
In case you don't have conflicts (account A don't edit the same objects that account B), service studio tell you that you need to merge and makes that for you.
If your doubt is about what appends when someone publish a specific module and someone else have that same module open, when the second one try to publish, service studio will trigger one of the two situations that I mention before (the merge and the conflict handler).
Hope this can help.
Best regards,
Ricardo M Pereira