Yikes!
I might have to be very careful of that. We've got a MASSIVE taint biome right near spawn - its not supposed to spread but I think it has; the chap running the server has planted a bunch of ethereal blooms with the hope of keeping it under control, but we'll have to see how that goes. Reminds me of the bad old days of Thaumcraft 2, when I ended up removing the entire mod because the taint was spreading far too fast and I couldn't research fast enough!
Is there a way of switching off the destabiliser without depowering, like with a redstone signal, and does that allow it to stabilise more reliably?
There's nothing in the thaumonomicon entry to suggest that it's redstone sensitive, and there's also the fact that it's right next to a hungry node and thus redstone may well get broken. Worth a try though. I intend to experiment tonight with teleposing the destabiliser away to see what happens.
I just don't understand why the creative world test suggested that it should be safe unless you get unlucky or try to run it at low power for an extended period, but when I tried it for real, it corrupted every time.
Oh, giving the power requirements would probably be useful. The destabiliser has a 100,000 RF buffer. It won't activate until the buffer is full. When it fills up, it will immediately consume 99,900 RF, leaving it with 100 RF in the buffer, and turn on. While active, it consumes 100 RF/t, but if you're only supplying that much then it will run with only 100 RF in the buffer, and testing suggests that that has a good chance of wrecking your node. If it runs out of power, it will turn off, and will wreck the node, unless it doesn't.