It isn't so much weight and fuel, it's weight and balance. And if you don't care what the pilot says about it then you are being excedingly dumb.

We have a lot of light aircraft crashes in Alaska, and a very high percentage are due to improper loading, either too much weight or weight that is not properly balanced. If a pilot is any good, he/she won't let you board with too much weight, and will be very careful about how and where all weight is stowed. I refuse to fly with any pilot who is careless about it.

Not crashing in the first place beats the best survival kit, every single time.