That does
not unmount the filesystem. It might help mitigate problems by turning off the recording software, but the filesystem is not completely unmounted. This is revealed by use of a filesystem check tool, like dosfsck in Linux, which will report that the filesystem was not cleanly unmounted. I've had filesystem checks on the drive recover recordings after following that procedure, but never any worse corruption. (Caveat: I've had my Tesla for barely over a week, so there may well be a chance of worse corruption than I've seen under some circumstances, even when following the procedure you describe.)
Speaking more broadly, modern OSes, including the Linux used in Teslas, cache most or all filesystem accesses. This means that data written to the drive may not actually be written to the drive when the program writes the data. Instead, the OS can hold the data in memory until it's ready to write data. This is done to improve performance; it lets the OS write data in efficient batches rather than piecemeal. In some cases, data can be held in a cache for quite a while after the application has finished writing. The drawback is that, if you write to a removable medium like a USB drive, pulling it before the cache is flushed to the disk will result in filesystem damage. Unmounting the filesystem flushes the cache. Unmounting the filesystem also clears the "dirty bit," which is set when the filesystem is mounted so that the OS, and disk-repair tools, can identify when a filesystem was improperly unmounted. Every OS provides some way to unmount filesystems, although the name for the function varies. IIRC, Windows calls it "safely removing" the device, and in macOS it's "ejecting" a device. AFAIK, Tesla provides no UI element to do this for its TeslaCam or music devices. Turning off the recording and waiting a few seconds is likely to minimize the damage, because the cache is likely to be flushed in that time, but at the very least, the filesystem's "dirty bit" will be set. There's also no guarantee that the cache will be flushed in that time period. If not, filesystem damage will result, and I've seen that myself.
Note that I'm
very familiar with this subject. (I'm the author of the
GPT fdisk partitioning software, which manipulates disk partitions, although not filesystems; and I deal with Linux every day in my day job.) I can say with authority that filesystem damage is more-or-less guaranteed if you unplug your TeslaCam drive with anything resembling regularity. To repair the damage before it causes serious problems, use of a filesystem check tool whenever you unplug the drive will help.