Since first owning my TS I have shamefully let to oil drop to the tip of the dip stick twice.
The shame and guilt over this weighs heavy on my heart. BUT, at least I caught it while it still had about two litres left in it.
I believe the real danger is that when the oil gets this low it is returning to the sump and being recirculated immediately, increasing temperatures and degradation and burning off of the remaining oil. The loss of the remaining litre or two of oil happens quickly resulting in actual metal to metal contact of hot spinning parts = real damage.
The fatal damage I believe usually occurs when oil has dropped to a level where there is no longer the sufficient oil to have a continuous circuit from pick-up, up to the head and down again. If air gets into the oil pump it seizes, after which no oil flows resulting in toast within seconds.
All this of course is my attempt to convince myself that my Alfa has been mistreated but maybe not seriously wounded by my shamefull neglect. To be fair, the last time I lost two litres in two WEEKS!! (Late night blasts back from Meath on N3 for a few days running)
Now every second day I leave the house and open the door of the car, I clip the bonnet, lift the stick, drop it back in, and drop the bonnet. 10 seconds tops. Just because you're paranoid, doesn't mean your Alfa is not trying to toast itself.