I've used Addi Clicks almost daily ever since they made their debut a couple years ago ....I've never had my Clicks come undone. The secret is in the 'click'. You just have to make sure you 'seat them' properly. The groove on the cable end has to line up with the dimples on the needle tip. Line them up (align them)...push....twist...release....click!
Because the 'finish' on Addi Clicks is sooooo buttery, I have a hard time griping the needle tip & cable end tightly enough to perform the push-twist maneuver...but I solved that by cutting out two 2"x 2" pieces of non-skid shelf lining. I use then to help me to do the push-twist part.
Anyway, most importantly...read your directions in the box. The wording and diagrams are very helpful. It's not rocket science. But you do have to take care to align the grooves and dimples.