Cats will investigate anything they can fit into, and they can fit into tight spaces. Always check your dryer before starting it. Its warmth and darkness make it an attractive nest. Plastic bags are as dangerous for cats as they are for small children. And don't forget your car.
Cats often crawl up under the hood for a warm nap in cold weather.
Get into the habit of banging on the hood before starting the car to rouse any stowaways.