Regarding storing gear under the front seats of your car, here's another random tidbit that may apply to some of you. My 2005 Honda Accord owner's manual warns you to not store any cargo or metal objects under the front seats. It even warns back seat passengers not to put their feet under the seat.

From the limited info in the the manual, the driver's seat has a seat position sensor (I'm guessing magnetic) that adjusts the inflation of the air bag depending on how far the driver is sitting from the steering wheel. The passenger seat has a weight sensor that turns off the air bag if it determines that an infant or child (or no one) is sitting in the passenger seat. Anyway, you definitely wouldn't want to risk interfering with such vital safety systems by storing stuff under the seats if your car is equipped with something similar.