This is basically the same as the Hellbent mechanic from MtG. A Last Resort condition will take effect for one-time use cards if it is the last card in your hand. Cards in play may also provide a bonus condition when you have no cards in hand.
The mechanic is almost paradoxical in giving you card advantage because to take advantage of it, you're basically playing one and a half card, for every card that has Last Resort; but to do so, you must have very little cards. Players will likely accuse you of having extremely good luck for top-decking(playing cards as you draw them because you have no card) all the time; however, this mechanic is just my integral design of the Rogue class as they don't have traditional card drawing for card advantage. Rogue cards are also intentionally low cost to leverage Last Resort.
Thanks for reading my borrowed-idea-but-obviously-renamed-to-avoid-copyright-issues suggestion on a new mechanic. Looking forward to seeing any comments, suggestions, or flames you have in mind.
Examples:
Note, visit the Decoy mechanics page for more info on it.