It would clog up a carb or injectors...if you had no filter. Most vehicles have some sort of prefilter on the pickup that would keep the sugar from even reaching the filter. That caramelization bullshit is just that as well...bullshit. I agree though, screw the inconvenience of a locking cap. Do something fun instead.
Just watched mythbusters on the sugar in the gas tank thing. Doesn't cause any problems. Bleach however rusts the tank over night. Leave it in a plastic can so they don't have any clues. It seems that moth balls may give you a bit more octane though. I vote you leave the .50 cal loaded with a flashlight taped to it so you can have some fun! I personally think thieves should have their finger and toenails pulled out and then be skinned alive. Same thing for left lane squatters.
Locking gas caps and gas doors just make things worse. We had this problem on our work vans. We parked the ones with the locking gas doors at the office and took the other ones home. We ended up with stolen gas AND crow bar damage to the gas door and surounding areas. Christmas time is prime time for theives. I just had one of my our wheelers stolen right out of my yard the other day.
One of my uncles found a good solution for the people who were breaking the lock off his tank of gas on the farm and stealing it 20 gallons at a time (two guys carrying two 5 gallon cans each through his fields). When the tank was almost empty he put the water hose in there and filled it partially back up. They cut of his lock one more time, ran back through the fields with their gas cans, and he found their car hydrolocked about 100' down the road the next morning. Dumbasses.
