Why would you want to suppress a warning though? It takes the same amount of time to correct the code as it does to suppress the warning and one day you will get an error and wonder why you never got a warning about it.
The only type of warnings I would suppress is deprecation warnings when I want to use some old code for whatever reason.
If you are using some old poorly written code filled with warnings you might want to spend a day cleaning it up as it probably has some faulty logic as well.