If you replace one USB device with another of the same type (same
manufacturer, same IDs, and so on) there's an excellent chance the
-kernel won't detect the change. Serial numbers and other strings are
-not compared. In many cases it wouldn't help if they were, because
-manufacturers frequently omit serial numbers entirely in their
-devices.
+kernel won't detect the change. The serial number string and other
+descriptors are compared with the kernel's stored values, but this
+might not help since manufacturers frequently omit serial numbers
+entirely in their devices.
Furthermore it's quite possible to leave a USB device exactly the same
while changing its media. If you replace the flash memory card in a