You would see that the rust sometimes in kitchen if you cook often. I still remember that stainless steel supplier in China is high quality without any rust in our daily life use. However, do you ever think about the reason for the rust of the 304 stainless steel?
 
Chloride ions are widespread in our world, such as salt / sweat / sea / soil and so on. The corrosion of stainless steel in the presence of chloride ions’ environment is quickly, even more than ordinary low-carbon steel. Therefore, use of environment requirements for stainless steel requires frequent cleaning to remove dust, clean and dry when we get them from wholesale 316L stainless steel. (So you can give him set a "misuse.") There is an example in United States: a company with a oak container containing a chlorine ion-containing solution, the vessel has been used hundreds of years, it plans to replace the nineties due to lack of modern oak material, the use of stainless steel replacement after the container leak due to corrosion 16 days later.
 
Under this situation, even for high quality 304 stainless steel, we need to protect it from damage of chloride.