Ian it is news to me that it might have occured, or be occuring - please email me privately if you have seen it happening - with member names you suspect, and we will take a look.
Rule 28 below clearly outlines the firm board position on it.
We have had a few geniuses in the past whose accounts were suspended by moderator concensus, sneak back and re-join, but their new "career" did not last long.
Oddly they generally post the same things, in the same manner, and often are dumb enough to use the same IP, which sets off a few bells eventually.
So thanks for asking, thread locked in case anyone gets any ideas - but unlike ebay -
our detection meter is pretty well honed here.

admin wrote:
28. Using Multiple stampboards.com Accounts
In general Members are allowed just one stampboards.com account. In the past some members have used multiple handles to harass or mislead other members. Multiple accounts will be closed and members involved will be subject to the disciplinary process.
Remember every Moderator can click on ANY post and see the IP address and city/suburb it was posted from and from which service provider. And also IP log where all posts and IP's from that member were from, and whether they match any IP used by any other member, at any other time.
It is that simple. The special add-on software we have here does it all - at a glance. Tell us you are in Adelaide, and post from Brisbane - and we can see that readily.