using "view cart" to update the quantity will also bypass the checking of available stock. So if you have stock of 3 and you put 6 in Qty and hit update cart, it will update to 6.
That should work properly if the items you are updating have stock tracking turned on and have a stock level set. The form will fail validation and an error message will print out. I don't know of any problems with this feature...
Joined: 11/05/2007