Hmm,
I just created a compilation, which was 6 seconds too long (cd 79:57, compilation 80:03), so I tried to overburn, which seemed fine, up until lead-out, when led turned yellow, rotation speed decreased, and finally error message popped in Nero.
So I put cd back in, and hey, everything's there. I do file compare, and files are identical.
So did it manage to write enough of lead-out, or maybe it's not needed at all?=p