I'm a beginning climber and am trying to resolve conflicting instruction related to tying into my harness.
During a recent outing a friend (an experienced climber, but not an instructor) was showing me the basics of switching from climbing to rappelling. The basic steps followed were:
1) Climbing to the anchor while on belay, tied in directly to the rope
2) Securing a sling to my belay loop by threading it through itself, then securing it to the anchor via a locking biner (first question)
3) Securing the rope to myself, then untying from it
4) Halving the rope, attaching my rappel device, and using a locking carabiner to secure the device to the tie-in loops (second question)
5) ...the rest isn't really relevant
So my questions arise from the usage of the belay and tie-in loops. I've been taught by a trained instructor that rope should never be tied directly into the belay loop as it can generate excessive friction and cause failure.
My first question relates to my friend's instruction to secure the sling to my belay loop without a carabiner. This made me wonder if we were misusing the belay loop. Her rationale was that the tie-ins were occupied by the rope, and since the sling would be used to hold my static weight (and not a fall) that there was no risk of excessive friction.
My second question comes from attaching my rappel device. I was instructed to clip it through both tie-in loops rather than the belay device. Again her rationalization was that the belay loop was occupied by the sling.
And a final question related to the first two: most of the reasoning for this approach was to keep the tie-ins and belay loop occupied by a single sling / biner / rope at any time. Is it unsafe to have multiple connections to a single point while switching from climbing to rappelling (e.g. a rope and sling through the tie-ins, or two biners through the belay loop if I'm clipped to both a rope and a sling)?