This is a good example how a simple and very effective piece of diver gear can fall into disrepute because of poor training and a lack of understanding of its proper use. A snorkel should be a simple mouthpiece and tube and never attached to a mask. Once the reg. is brought into use the snorkel should be stowed and never left dangling from the mask or anywhere else. A snorkel is not an entanglement if it’s used properly. Just shows the level of training the people who banned it got.At higher levels of diving (tech, wreck, cave) you'll find that it is considered an entanglement hazard and forbidden in training. The long hose setup normally used in these types of diving can catch the snorkel when you share gas with your buddy and dislodge your mask. The location of the snorkel by your chin can also hinder deploying your necklace regulator.