Blue Jay, the cat shat in your SHOE?! Geez, mine have the good manners to hide it in the laundry pile. ;-)
In the cases of both your cat and your dog, the cause of flatulence is probably a change in diet. It doesn't even matter if you are feeding them top of the line, break the bank food like Kat gives hers; if they are eating different food this week than they were last week, they're going to be stinky for a while.
As for the shitty shoe...Was her box accessible and clean? Mine go where they please when the box gets full. Otherwise, I don't know; maybe the message was "Thanks for taking me in and giving me a lovely new home. Allow me to make your shoes more comfortable."
Our cats have no flatulence problem unless they are eating cheap food, especially the canned variety (which also causes them to emit deathlumps in the litter box). Sometimes if we have switched from one brand to another they get stinky. They do fine on Purina ProPlan or the brand called 365, which we pick up for very little money in the local health food store ($1.99 for 4 pounds!). They do eat a lot less of the 365 than the tastier ProPlan, but they are beautifully healthy on both.
Not that anyone cares, but it will make me happy to tell you that we have four kitties; Houdini is 10 and the newest addition (black cat, green eyes, total wimp with gorgeous siamese-shaped face. quite the yowler; he came with the house we just moved into), Lydia is our first kitty (tortoise-shell calico with yellow eyes and a half yellow-tiger and half black-tiger face, part Siamese by the sound of her, total lovey; 5 years old this coming April), ZZ the former mama cat was rescued from negligent neighbors after five litters of babies (white with black tiger splotches all over her, also a half-and-half face and green eyes and bunny-like fur - probably from consuming so many of them...She turned 5 in October but had all her babies before she was 3), and Gilbert (grey tiger with spots instead of stripes, green eyes; totally timid but hounds his chosen person -me- half to death, he turned 2 in June). Whew, I feel better now. :-)