Sorry, @Ealfardan, our posts crossed. I am thinking along the same lines. I was actually more concerned originally about what I call “orphan” transactions. There have been a couple situations in past years where deletion of one thing leaves something related hiding in the database with no way to get at it. This is not quite the same thing, but the experience for the user is very close to that.
Re-reading the thread you linked about expense claims refreshed my memory on that issue. I think a solution is to show all transactions, including pre-start-date ones. Those before the start date can be in red or gray, be restricted to the bottom of the list, or something. But it does seem like they ought to be more accessible.
Given that I thought the expense claim situation was a bug, I suppose this one qualifies, too. I will move the topic to bugs and edit the subject.