going beyond your bounds

[MLT]

Derek Parnell Wrote:

> 
> So remember, assigning one array to another is just creating an alias to
> the original array. You end up with two arrays pointing to the same data
> buffer.

Yes. My question relates to what happens when you go beyond the bounds originally assigned.
Why does an extension of an array
b.length = b.length+1 ;
erase (initialize) the data that b extends to?