And that meaning should be unambiguous. Roger means you received the whole message, nothing more.
Ah, so the next time I receive some incomprehensible jibberish from a Geordie/Scottish mate of Mad Jock, and I say "Roger" he may rest assured I have understood every word. Same goes for Serbo Croat and Esperanto transmissions as well I suppose.
If I were a controller and seriously believed "Roger" to mean simply that the transmission had been received but not necessarily understood, then I would feel duty bound to ask the recipient to explain to me in further detail exactly what it was he understood by my transmission. This requirement would make a complete mockery of the use of the word under any useful circumstances whatsoever.
There are many reasons one may get a 'roger' from someone who received the whole transmission, but did not understand
Please list these many reasons. I have forgotten them.