Right, the P-fare mentioned above is fully changeable without penalties, so if there is a 24-hour time limit on cancellations, I could technically just call in an hour before departure, ask to change the date to a month later, and then when the ticket is revalidated call to cancel and refund the ticket. Sounds easy, but my concern is that LH probably thought about this too.

Maybe I'm being too paranoid? It's just that I have experience with dealing with LH's customer service and it's not been very positive, that's why I try to cover my bases whenever I sense a possible future interaction with them.