has anyone seen a hood switch like this?

My 2008 MDX had a car starter installed before I bought it.  I am now trying to get it running (I bought the vehicle used and have no warranty on the starter).

Everything looks good under the dash, except the hood trigger looks funny to me.  The wire goes throught the fire wall and attaches to a stub under the hood.  See attached photo. Has anyone ever seen something like this.  How does it work?

When my wife get's back I'll look again.  It must be a tilt switch (instead of pin switch), either roller ball or mercury.

Thanks

With today's alarm technology, I really don't think you have to worry about any false alarms with this sensor.  If you are parked on a steep enough hill for the sensor to see ground, the alarm should notify you of an open zone.  If it is not open at arm, and it is not parked sideways on a narrow Seaborne vessel, it should not false.  The sensor is probably more important for the remote start unit.  If the hood is open and a mechanic is under the hood, it is there to not allow the vehicle to start and take a finger off.  

You asked how it works, there is a ball that rolls from the tip of the nipple to the back of the device when the hood is opened.  On the back of the unit is also the contact that the wire is connected to.  When the ball rolls to the back, it shorts the wire to the chassis of the device.  This applies ground to the wire.