[development] Why is Block table delta field only 32 chars?

[Jacob Singh]

I spent a good long while trying to figure out why my 38 char delta block 
would show up in the admin_display but would not get assigned to a region.  I 
realized that UPDATE ... WHERE delta= "full 38 chars" was not going to find 
my truncated entry created by _block_rehash :(

Is there a reason to limit the length of this field?  

Should I submit a patch to check for this in _block_rehash and alert the user?

Best,
Jacob