Folders are lockable. That was my point. Further, there are many reasons for owning one besides that fact that you can carry them, like a precious child, wherever you go. And the alternative need not be to leave the bike at home. I am fresh off of my early-newbie purchasing experience so I'm speaking from that perspective (compare my 5 posts here with the 2,428 from Folder Fanatic,) but sometimes a beginner's eye picks up a point or two neglected by old timers.

As a general impression, I'd say there is a strong bias against even discussing folder security beyond the "fold-and-carry" strategy. There's almost a sense that locking violates the "spirit" of folder bikes. Likewise, the very helpful sales people at several shops I visited all discouraged any detailed discussion of locking.

I'm not being cavalier about security and theft, but I'd discourage anyone from buying a folder (or car, or cellphone, whatever) unless factoring into the cost sensible security options----and these might include owning more than one locking choice to suit different circumstances and uses. The expense of owning a helmet or night lights should not be not contingent on the rider's personal wealth or value of the bike. In this respect, making full use of a bike on a college campus requires, IMO, the option of a beefy locking system.