Uwstlth, as I understand it the Ordinance doesn't really prohibit anything, it just gives the city the authority to order the average bonehead (novice or experienced diver - snorkeler or scuba) not to go into the water if it looks like their activity might result in city resources being used to rescue that person or do a body recovery. Note the language says "may prohibit." Thus, taken literally, if a lifeguard thinks your lack of a snorkel, or lack of a buddy while snorkeling, somehow creates a hazardous condition then they have the right to order you not to go into the water. Anyway, that's my 2 psi worth of opinion on the subject. (Personal opinion, not legal opinion - so no one come crying to me saying, but, but, but... a lawyer said I could...)
Mark
"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968)