I'm assuming this kind of behaviour is relatively abnormal. Regardless, I strongly disagree that there should be auto-suspensions.
In the name of transparency and consideration, all of the situations should be evaluated on a case-by-case basis by a moderator (i.e., notify a mod automatically would be nice). Even if the situation is perfectly clear, IMO there needs to be a fair process of trial and appeal before a suspension is given.
Moreover, even if a user's content is flagged a lot, there are varying degrees of offensiveness to the content, past history, etc. While it's unlikely a user would be given a more lenient suspension, it could be decided that a user should be suspended immediately, or for a longer period of time, given the nature of what was posted.
Any kind of auto-suspension system would not be able to evaluate the situation the way a mod could. While that does bring a level of subjectivity to the process, I trust the mods to be fair and take action based on what is best for the site.