While I agree that checking luggage the night before is unlikely to be allowed, I have checked luggage in well in advance of the 4 hour limit (in the am for a pm flight, same day domestic) within the last 12 months. Problem - for city pairs with multiple daily departures - the luggage is placed on an earlier flight and goes round and round on the arrival carousel while you are still hours away, just asking thieves to help themselves...
No, definitely not paranoid here. lol.