Yes, we all have,
at one point or another. One of the main ways that diseases and parasites
spread is through the consumption of food and water contaminated with feces.
This sounds like
urban legend to me. It would take a heck of a lot of hydrogen to explode
a toilet in this manner, and intestinal gases just don't have that much.
Also, any flame would just flare up briefly. With an open toilet, you couldn't
get up enough pressure to pop the pot!
Yes, meat protein
is rich in sulfides, resulting in smellier farts and poop. This is the
reason that the poop of carnivores such as dogs, cats and snakes smells
worse than the poop of herbivores such as cows and horses.