Yes GLH, as John H. pointed out, it's a question of pride in workmanship. If a few strands at the end of a run of thick speaker cable were cut it wouldn't be at all analogous to a multi-lane superhighway suddenly narrowing to a one-lane dirt road. If the total resistance of the length of cable was,say,0.20 ohm a few cut strands in the last half inch might increase it to something like 0.2000001 ohm. In fact if a thick speaker cable was making it difficult to connect to a particular terminal it would be okay to intentionally cut off enough strands on the stripped end to allow for an easier fit.
