http://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_uuid The fifth number is an IEEE 802 node number that provides spatial uniqueness. A random number is substituted if the latter is not available (for example, because the host device has no Ethernet card, or it is unknown how to find the hardware address of an interface on the host operating system). In this case, spatial uniqueness cannot be guaranteed. Nevertheless, a collision should have very low probability.

The MAC address of an interface is taken into account only on FreeBSD and Linux. On other operating systems, MySQL uses a randomly generated 48-bit number. Хотя от копирования образа виртуальной машины это не спасет. А в массе других случаев добавит проблем легальным пользователям.