That's been my observation as well.There are very few absolutes in beekeeping. I would say that your beekeeper friend is not 100% accurate in his statement. It is generally considered a "good sign" when you see lots of foragers coming back loaded with pollen. It is an indication that brood-rearing has been kicked into high gear. But to say the opposite, that NO pollen will be brought to a queenless hive, is not necessarily true. However, I have had queenless hives next to queen-right hives and have noticed that queenless hives seem to bring in far less pollen than their queen-right neighbors.