The changes would be made to prevent stalling in the first place. Whether someone is skinny or muscular, programming changes to facilitate progress and prevent a stall is a better idea than resetting, especially multiple resets. Eventually, a novice is going to stall because the SRA cycle becomes longer than 48-72 hours. When a session becomes too grindy, with sleep/nutrition/etc. accounted for, it's probably smarter to do something different the next session (i.e. switch to advanced novice or HLM) than to carry on and miss reps.
If someone is too skinny, in your example, he or she isn't going to gain enough muscular bodyweight in a week to get back on track with LP. If they stall because their bodyweight is low, they would have to switch to some form of intermediate programming. And so on and so forth.
I agree, but the true beginner can't do this alone. A new lifter doing SS for the first time w/o a coach doesn't know how close to a stall they are. They should run the program as-written up to a hard stall and reset a couple times, so they learn the difference between "hard" and "impossible".
Without a coach, their judgement about program-tweaking is pure shit. Speaking from personal experience here :-(