Earlier quoted context omitted.
The same is true of digital bathroom scales. In fact almost all consumer grade digital scales have “fake accuracy” built into the firmware that ensures the same exact weight shows up when you step on the scale twice in a row, even if you pick up e.g a quarter-pound weight in your hand the second time
Yes, but do you(or someone else) have a recommendation of which scale does not do this? Something that's not consumer grade, but not "enterprise cost"
Measuring human weight is harder than it seems (we don't stay still).
Most scales use a strain gauge sensor that detects bending of a metal arm through changes in resistance. It's pretty noisy and needs averaging. There's some integrated circuits to relate the resistance to weight. Most do some factory calibration only around the target weights (median adult weights).
Look instead for a scale that explicitly states that it is accurate over the whole range (e.g. baby to 220lbs). Usually there's tradeoffs - e.g. the displayed weight won't 'settle down'. I have one like this and it works better than any previous one I had (tested by adding calibrated weights), but I hesitate to recommend since it's a low cost consumer model.