If AmigaOS4 was the dominant OS then the l337 script kiddies would have the time of their lives. Without memory protection and multiple users (or more accurately, multiple levels of authorisation) it is incredibly easy to cause havoc. Mix into that the fact that no-ones ever really tried to compromise an Amiga, there are so many possible vectors for gaining access to the system, so much old software for which online security was not about when the internet really took off for home use.
I even seem to remember there being an exploit in MUI a few years back (although it required a bit of social engineering) that could give access to a machine quite easily. There are probably millions of these kinds of things lurking about. Security through obscurity was about the best thing we've got.
