Sometimes it is agreed that the stakes are doubled when the turned up wild card happens to be a printed joker. In this case in the 2-deck game there is just one joker available for use as a wild card. Whoever is dealt this card or picks it up in the course of the game has a strong hand, though not a sure win.
Alternatively, some play rummy when a printed joker is turned up, all Aces are treated as jokers (wild cards) and the stakes are not raised.
Some do not award a double score for hand rummy.
Certain groups deal 21 cards each for up to 5 or 6 persons with varying stake rules, bonus, and penalties etc. I have not yet seen any details of this version of the game. Check out more Rummy Variations.