No, I used the Add Swap Partitions command in Slack-9.1 Setup. Using this command doesn't allow you to skip fsck'ing the drive. I've tried skipping it once (planning on just adding them to /etc/fstab manually), but wound up with out-of-memory errors during package installation.
There are multiple reasons -- probably unfounded -- why I have swap on both drives. First, I had been trying to install Linux from Scratch, but since my hard drives weren't large enough (I was always about 500 megs too short) I abandoned that idea; I had both drives set up with about seven partitions each. When I decided to reinstall Slackware I said "Screw This" and just made big partitions. Not efficient at all, really.
Secondly, it's a hangover from Windows. Putting the pagefile on a different physical volume from Windows and/or your most RAM-intensive apps is quite obviously much more efficient than keeping the pagefile on the same volume, because both drives can run concurrently, avoiding thrashing. Splitting between two volumes is even more efficient because now Windows can use either volume for swap space.