If you want to do it it can be done, though. You can intercept the mount
system call using LD_PRELOAD and about 10 lines of C, or you can write an
/etc/fstab line for /mnt that specifies noatime and your usual USB device
(perhaps sdb1, YMMV). If you write the fstab line at least "sudo mount
/mnt" will mount with noatime, and you can write something udevish that
runs mount and does it the way you want it.

Arnt