This will work without much extra effort because there will always be
more notices (higher value) than conversations (so no collisions).
But please run upgrade.php to avoid having an autoincrement id on
conversation table.
Installations using code after 2014-03-01 will have identical
conversation IDs to the initial (conversation root) notice IDs. This
will not affect older installations, which will have very different
values.
The parent class for our database objects, Managed_DataObject, has a
dynamically assigned class in staticGet which objects get put into,
leaving us with less code to do the same thing.
We will probably have to move away from the DB_DataObject 'staticGet'
call as it is nowadays deprecated.