KMD - Apologies, I thought you were a pilot. I would speculate the software allows the THS to remain at it's upper limit because thats precisely what the pilot was commanding. There's got to be an approved upper limit to THS position somewhere, and if it's approved then having the THS at that position is not necessarily unsafe. There are numerous failsafes to counteract THS runaway or uncommanded movement, but if none of these failsafe triggers have been activated and the pilot is commanding nose up THS movement then as far as the machine is concerned it's situation normal. When an Airbus enters alternate law it's because the computers don't have sufficient information to reliably keep the aircraft within the normal flight envelope protections. I would suggest the more sensible option in that situation is to err towards greater control authority for the pilot.