We are currently defaulting to dt_from_string in code, we could just set `NOT NULL DEFAULT NOW()` to get a more consistent behaviour couldn't we? I see this as a good starting place for moving C4::Circulation::AddIssue to Koha::Checkouts->store() eventually.
That seems totally reasonable to me now that we can set the database timezone to the Koha timezone!
I like the idea, but we need to think of bad data and the upgrade process.