You aren’t going to somehow increase trichome coverage and/or potency with 48 hours of no light. Plants use light to make those trichomes.
2 days of anything isn’t going to make a difference one way or the other.
Just an old stoner myth that remains persistent for some reason. No shortage of those.
Don’t split stems or fuck with the plants more than you have to. The biggest yields come from proper light, nutrition, airflow, environment, and genetics, not some old wives tale folk magic. You’re far more likely to kill the plant from an internal infection than you are to increase yield.
Cannabis cultivation, for a long time, was done primarily by counterculture weirdos underground away from other growers. There are a lot of holdovers from those beginnings. A great example is someone telling me they crushed up birth control pills and watered them into their seedlings to “help make them female”. The folks growing dope in cornfields didn’t take botany or horticulture classes so there’s these artifacts of “folk wisdom” that sorta make sense if you have no formal education, and get passed on to whoever they taught to grow.