In reply to mgb:
To be fair to MGB, who's on the receiving end of quite a lot of dislikes, I've used "fixed" abseil points on crags in the Lakes on a number of occasions (where "fixed" means a loop of decent rope and a crab, or similar).
I've abbed off "fixed" ab points on (at least) Gimmer (from three ab spots), Raven, Middlefell Buttress, Gouther, Lower Falcon and Shepherds. And I tend to really appreciate a stout bit of cord or whatever so I don't end up wasting my own slings and crabs.
In fact, I almost never take tat and an old crab with me to the Lakes, precisely because I know the ab will either be a walk or a fixed ab point, unless it's unplanned, in which case I'll try to recover my gear or be happy just to get to the ground in one piece...
I'm sure most people have a similar approach, so I'm not sure why the great pretence to some sort of ethical purity, re. abbing off others' tat.