I agree with Sarges reasoning. Statistics mean little when it's you that it happens to. I'm sure those that have had the locks engage improperly feel better knowing it isn't statistically significant.
Regarding the Ruger/Smith extractor rod question, I don't see it as a step up in reliability to go to a Ruger because of that single issue. Rugers have transfer bars. Transfer bars occasionally break. I've personally had more tranfer bars break (3) than Smith extractor rods back out (2) and cause trouble in the 35 or so years I've fooled with them both. I torque extractor rods, and have never had one come loose after being torqued.
"Far better it is to dare mighty things, to win glorious triumphs even though checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much because they live in the gray twilight that knows neither victory nor defeat." -Theodore Roosevelt-