I've always taped my rings, all of them, including the one holding the lower main block to the traveler car. It's too easy for a line to catch on one and pull it out. I use rigging tape for all of the reasons mentioned above.
I have seen at least one top racer use dual quick pins in each of his side shrouds. His theory was that he could safely make adjustments on the water (leapfrog them over one another to raise/lower the shroud).
I used to use a quick pin on my Hotstick, until the little ball froze in place (as mentioned above). Ever since, I just use a cotter pin and tape it. I rarely remove it from the crossbar anyways.