Not saying VNC is to blame, but there are a number of folks very gravely concerned about the insecurity of most SCADA systems. When your infrastructure and operations are built on hardware and software expected to last 30+ years, it's hard to consider the security implications so far out.
I think it is unreasonable to expect networked software to stay secure for that long. If it isn't networked in any way then sure, that might work but then again, 30 years is a long time.
Adding remote software control to physical things like water treatment and electrical systems adds a lot of convenience, safety, and saves loads of money but perhaps some of that savings should be spent on more vigilance in regards to security.
Not saying VNC is to blame, but there are a number of folks very gravely concerned about the insecurity of most SCADA systems. When your infrastructure and operations are built on hardware and software expected to last 30+ years, it's hard to consider the security implications so far out.