I used to use lock laces on my running shoes (triathalopes bang on about them for speed of putting shoes on in transition) but found that they don't seem to hold the tongue in the same shape/place as normal laces. I found I was getting weird pressure points that went away when I returned to normal laces.
I couldn't be bothered to work out how to re-lace my shoes with lock laces, which are thinner and rounder than the original wide/flat laces, to avoid this.
I think I've got about 5 pairs of unused lock laces somewhere, if I find them I'll offer them up for free (or a promise of a charitable donation).
OK, 4 sets (1 black, 3 red) available. PM away. Gone!