Well - i know it isn't- i just did that for fun!
I don't think there's too much of a problem because the re-burning tends to use less laser - subsequent burns do less work on the layer .... or so it seems
It's only a small wear on the focus / tracking as the WOPC constantly kicks in ....
I don't mind - with 3 benq's
My liteon has done this one like many times - it's like i had done it probaly 70 times, also sabotaging EEPROM and burning strage rings, overspeeding till i got silver discs ... harsh treatment, but it's burns are still star quality on the RICOHJPNR01... [do not try this at home - laser burn out is definitely an issue at that power].