This is perhaps my favorite one. By default, SQLite doesn’t actually delete data:

  The default setting for secure_delete is determined by the SQLITE_SECURE_DELETE compile-time option and is normally off. The off setting for secure_delete improves performance by reducing the number of CPU cycles and the amount of disk I/O.

That isn't much unlike most filesystems (in fact, on CoW filesystems, even with this setting the data is likely to still be hanging around on disk)