Well if they wear to the point where they actually length, they could be binding; that's possible. Also use some emery cloth inside the bell if you feel any rough spots that could snag the shoes (although this is unlikely). With no springs, what keeps the shoes off of the bell at idle? They must rub some, does the CB get kind of hot on that thing?

Maybe this is a good time to consider dumping the stock clutch setup anyhow, replacements are inexpensive and will provide real-world improvements.

Good luck both of you...