well i'm not saying literally. but reaching critical shut down temperatures isn't good for long term life of the CPU, or GPU for that matter. 🙄
just have it out on the table, closed but running. If you leave it in the bag you will heat it up enough so you'll have a screaming banshee in a bag. even closed on the counter will not guarantee silent running. A few times i've done it and woke up to a hot computer even though it was "idle"
in the first generation of the MBP where they mysteriously turned on in people's bags, it was still running despite reaching burning hot temperatures (even in a closed bag). Dont rely on a temperature activated shutdown.