You will notice that when the cards run out in the machine the staff go check it and replace it with the new deck. For V4, take a notice when the staff changing the old deck with H, play in that machine that has some Siegfried cards on the deck. If the card is stuck, go call the staff again, if you are lucky maybe you will get Siegfried. Heard that when V3 generation a staff has been changing a machine deck with Deck F. Take a look what deck the staff change the deck with a deck, the letter you notice sometimes can get a chance for you getting those rared cards!!!
If you missed it so you will just have to play lots of times, until you get Siegfried. Make it easier by checking what deck inside with the staff's help... when the staff open the machine only the 150 cards on it, the deck cover got thrown away, so we don't know what card in it!