Interested in this, as I'm looking for new 'cafe' lock, since my small 'oxford' 1.5m combn lock died. Found I couldn't undo it post coffee stop, after 10 mins I, ahem, spat on it, and moved the lock rings quickly to lubricate - which did the trick. Thankfully.
I use a frame lock which is standard bolted to my frame. No need to rummage through my bags to find it.
I think our insurance policy states - needs to be locked to an 'immoveable' object ....
edit. went for this 'cafe lock' ~150g *
IMG_20190803 by
ao, on Flickr
* I'm not doing PBP