Well I usually just ask questions, but maybe I get to add something for once.
IMO 17lb leader is perfectly fine for sox. Lighter would work, but as someone said, yank it in and take it home.. You also might consider heavier in case you get into a spring. I think some might say that 17 is good enough for a spring too, but with all the people and the type of fishery it is, you probably don't have the time to stand there playing it for 20 minutes while 40 people are waiting.
I think you have one of 3 problems depending on where your leader broke;
If you were left with a couple of inches after your swivel, your weightprobably broke it off after banging it a bunch of times, so use a leader saver.
If you were left with zero leader, then maybe you need to refresh your knot tying skills
Or 3, you sure it was not a Spring that you had on?
Just my thoughts.
Rob