Post Dating Items

I often find expense receipts that I forgot about from last month.  When entering them, I blindly click on the current day for the displayed calendar.  Only after re-listing my expenses do I realize that I've post-dated that expense to sometime in the future instead of posting it for the previous month.

A friendly warning like, 'hey dumbass, you're trying to enter a future expense' would be most welcome for those of us with calendar dyslexia.