To add to Fonty's comments.

The switch is just that, a switch. two peices of metal that when the card is slide it, pushed one side of the metal to contact the other side, creating a curcuit. So "jumping" the two wires, will remove the chance of the switch itself being the issue.

think of it as a light switch. you have two wires that connect to the light switch. When the light switch is in the off position, the current doesn't flow from one wire to the other (completing the curcuit). When the light switch if on, the circuit is completed, and the current will flow. Connecting the two wires together (you don't want to connect them when they are live, you may shock yourself!), you do the same as switching the light switch to the on position.

This is what you are doing with the card switch, just by passing the switch. The card still needs to be in the card holder, as there are other circiuts involved with the card that need to be completed in order for the bike to work.