I tend to agree that what I am describing should not be possible, none the less to date this has happen five times, usually with a week or a little longer between episodes, this all started a few months ago with a griefer rezzing security orbs on the sim, these initially ejected people from the sim by way of returing them home. Again this was using disposable accounts, we locked the sim down by restricting who could rez objects and the attacks stoped for a while.
The owner has been in contact with LL and were running a performance and security evaluation on the sim, they thought that this was one of the estate managers as well, until the Linden was added to the estate ban as well by person / persons unknown.
Re writing a tpv to achieve this seems like a lot of effort to go to, unless there are already viewers out there that can be made to do this, I thought that tpv viewers had to meet LL aproval before they could be used, otherwise they were blocked.
Regards