In reply to beardy mike:
Mike, I really appreciate the advice, although it is orthogonal to my original question.
> if you are tied in with rope, it provides enough dynamic stretch to reduce the impact on the anchors
You can't tie in with a rope if you're leading the next pitch as well (e.g. block-leading, or leading the whole route).
> and you're not carrying a load of kit which is just extra bulk and faff for a compromised system
I was actually thinking that
if I already had this kit with me on a route, would there be any reason not to use it.
> If you are clipped to bolts, unless they are rotten bolts, the anchors aren't going to fail.
Or rotten rock, etc.
> If you're at a trad belay, put in enough gear to never have the fear of it failing. If theres not enough to prevent the anchors from failing, MOVE to somewhere that does.
That's not always an option, is it? I'm sure many of us have ended up with the occasional anchor that we'd rather the second didn't fall on.
> You simply don't need a VF lanyard. It's the wrong piece of kit. ...you're dragging around 50m of rope - use it!
See above.