I guess I've been living dangerously for a long time now. I also stack my bi-wire cables but am careful not to move my speakers at all, never walk near my cables (they're not in a traffic flow area), and I'm sure to really tighten my binding posts well. My binding posts look like a rat's nest compared to most as my speakers ARE bi-wire designed but after experimenting, just for fun, with doubling up the runs onto each terminal and trying another pair of cables in addition (not the same brand but I ran them on my bass terminals), I heard a definite improvement in both top and bottom. With that in mind, I bought another identical pair of my original cables (Harmonic Tech Pro-9's) also/purposely bi-wired (to be "future proof" in flexibility) and now I'm running a total of 8 spades to 4 binding posts... no, make that 10 spades because I've had my Walker High Definition Links to my mid/tweeter terminals since day 1 also, so these binding posts are actually holding 3 reasonably thick spades stacked up, per post. Besides the obvious "major event" status when I do my connection cleaning ( I Like Caig's De-oxit), this set-up has yielded the best sound for me... adding the second pair of identical cables sort of synergized the whole scenario, if you will. That is a great idea though, Justlisten, but did you say "Used" credit cards? or cards you wanted to keep from using anymore? Just be careful back there... Happy Lissn'n.
