I bemängle here not the product itself, but the operating principle. The lip will inevitably any remaining loose contamination remaining on paint wet paint or it has just been blown away by the wind, draw on the paint and cause a slight scratch. Therefore, the more cautious vehicle keepers prefer using a fluffy, absorbent microfibre cloth (eg Orange Babies drying towel) that does not push those dirty grates over the paint, but receives and can disappear between its fibers. The "Sunday keepers" but is this little risk to be sure no matter.
