Yup, there are and were plenty of great pros who have/had bad habits. In the old days, they used to lick the tips of flashbulbs to "ensure good contact'- that solder on the tip has lead in it. Some folks pace a 9-Volt battery on the tongue to see if I still live- that works well until some idiot did it with a 90-Vilt radio-B battery. Many retouchers would place brushes laden with aniline and New Cocaine dies. Some of that stuff is poison and the "spit" did not do the negatives and prints any good. In the old wet darkroom, some very capable operators would skip the gloves and dip the hands in all kinds of chemistry that are not apparently corrosive but can defuse through the skin and cause cancer and another serious disease. Some "rocket scientists" would mix potassium Ferocynide with a rapid fixer containing sulphuric acid because it bleaches faster than a regular fixer with acetic. acid. I guess they liked the smell of roasting almonds. I know it may not have killed them right on the spot but I ain't one for turning a poorly ventilated darkroom into a possible gas chamber.

I suppose if you are a war photojournalist working from a trench or a foxhole with incoming ordinance all about, some spit and your shirttail, especially if it has been laundered many times, might do the lens cleaning job. Under ordinary circumstances- buy a proper lens cleaning kit!

People do all kinds of dumb things- even smart people do dumb things. Why emulate someone's bad habits, will it improve your photography and make you an internationally acclaimed photographer?

Saliva is good stuff- it lubricates your mouth and helps you digest carbs. My advice- keep in in your mouth and off your equipment.