smartctl causes 3ware/LSI 9750 driver to print an error in Windows 7 system event log - "The driver detected a controller error on \Device\RaidPort0." 
This happens with smartctl -i /dev/sdx , -A /dev/sdx, -x /dev/sdx etc. Interestingly, errors do not appear when using the alternate name /dev/tw_cli/c0/p0. 

The /dev/sdx in question is a "disk" obtained from --scan output and it is actually a RAID volume, reported as a disk. 
So my questions are -
1. Why does --scan return RAID volume instead of physical disks in the RAID controller? 
2. Why does smartctl cause 3ware to log an error message in the event log.