I've had my G&T for the night so am feeling somewhat ambivalent. The OP questions safe operation - and he's correct to do so. I hold a view which I think is shared by some that, gauging an acceptable level of personal risk against convenience that I/we are prepared to cut some corners. But, please understand that doesn't make it safe. I wouldn't pretend for a second, or promote that nipping up a cutter in a spindle with your hands/body/spanner anywhere near is "safe" in the event of either hardware or software failure.

Right!, where's that blasted cat?