As to auto defrag, no, a memory card is never defragged. Formatting the card does make it be empty, so the next data probably will be orderly.
But fragmentation really does not matter to memory cards. Fragmentation and/or defrag has no meaning for solid state devices (flash cards, SSD drives, etc).
Hard drives spin, and the head follows tracks on the platter surface, and so there is efficiency advantage of having the next cluster directly follow the previous. Otherwise, the drive has to stop reading, and seek to find the right track for the next data, and wait for the rotation to come around to the right spot again, and that is slow. Esp if it happens very often.
Solid state however directly addresses each byte, it really could not matter less where it is. There is no movement or delay involved to get there. So yes, solid state possibly is always fragmented, but it really could not matter less. Each byte is directly addressed anyway. This is one advantage, no seeking as such.
Computer systems (Windows) routinely disable defrag for a SSD drive, for that reason. It serves no advantage for solid state, it would just run up the usage count for no good reason. It would actually be undesirable. Flash devices have a (very large) maximum count of how many times each byte can be rewritten.
