No doubt it's all cleverly boxed off in the Regs, but being an armchairist, my only query would be on safety issues - previously (& possibly now?), there have been Regs to allow components to be changed if their use could be considered dangerous, and a gearbox with a failing bearing could just about sometimes occasionally be a bit on the dangerous side of safe.
Being an old git, stuff like this makes me think back to Colin Chapman making components that lasted 1/2 a lap longer than Race distance (if the driver was lucky)...and also to Jim Clark, who had to manage without the assistance of chemical biological physicists telling him his gearbag was about to go bang.
