The practice is not used, nearly as much as in decades past. The "Solingen" blades were often etched because they came, heat-treated, and stamping then was not practical.
Other "etching examples came from the hammer-stamped trademark being "lost" in the knife-making process. At times they (the blades) were stamped too lightly or when the blade was not as "hot", if you will, resulting in a light stamp. At other times, in the process of grinding, buffing, etc. the stamped trademark would not be properly legible...hence etching.
I am positive there are numerous "more" examples but this (hopefully) gives you a little background on etching. The blades being put out today, at least from the numerous blades I handle, almost always have a good, easy-to-read stamped Randall trademark.
Hope this helps,,,and Stay Sharp,
Capt. Chris