I too am a happy Swift owner, and the Swift threads on this board have been a great resource. Early on, my seatpost slipped down just a little during my rides. Turns out I had too much lube on the seatpost. I wiped it clean with some Simple Green and applied a very, very light coat of TriFlow Grease (not the oil) to the post. That solved the problem. Also, the post stays a lot cleaner with less grease.
Gaerlan sells a roller thingy which I put on my Dahon before I sold it. I've never experienced a chain drop while riding my Swift (knock on wood). But mine is not stock, it was built by Peter Reich and has a DualDrive on it, and the alignment of the drivetrain somehow makes it worry-free.
Here is the link for the Gaerlan roller:
I wish you luck and happy cycling!