Most of the time an experienced and reasonably intelligent splicer can cut in a DC without toning legs even in underground plant. It's just a matter of being familiar with your as-build maps as well as your splicing maps. When I was splicing I would almost always figure rather than tone which leg went where and was wrong on about 1 out of 20. The ones I was wrong on, I caught myself when I checked the deadends or set up the next active downstream. It's just a matter of thinking about what you are doing.
This is CABL.com posting #81977. Tiny Link: cabl.co/mvun