Citation :
702.56b. A forecast ability may be activated only during the upkeep step of the card's owner and only once each turn. The controller of the forecast ability reveals the card with that ability from his or her hand as the ability is activated. That player plays with that card revealed in his or her hand until it leaves the player's hand or until a step or phase that isn't an upkeep step begins, whichever comes first.
Quand tu actives Prévision, la carte reste révélée jusqu'à la fin de l'entretien (sauf si elle quitte ta main), donc quand tu activeras la seconde Prévision et révèlera le second Hussard, le premier sera toujours révélé. Aucune confusion possible.