Hello Geo,
I can tell about my solution to locking my Strida. At the beginning I was ready to follow the recommendation for secure parking as folded (manual page 11). But I realized my U-lock from good old MTB days back in late 80’s didn’t have enough reach. Any cable lock was not my choice so only folding lock remained on shopping list.
My choice was Abus Bordo 6000. Especially it’s rubberized gage and straps makes mounting on rear rack ideal because of the ideal dimensions, like it were created for Strida, just have a look:
Now I usually park my Strida unfolded but there are situations where even the reach of my lock isn’t enough or I must struggle a bit how I should “route” the lock links to get it done. Because the perfect fit I keep my lock on rack all the time, even during photo shooting…
Just my 2 cents…