Errors are there to stop you doing things are not allowed like walking across Niagara Falls on foot (without any ropes or anything). It just can't be done, so the compiler say "No".
Warning are there for things that you might get away with, but you probably shouldn't try, like walking across Niagara Falls on a tightrope. Yes, some really, really skilful people can to this, but it's more likely that you're going to get wet (at best).
If anything, you should go the other way and promote Warnings into Errors and close the door on all these potential problems.
Failing that, if you really can't avoid a warning, then suppress that single instance of the warning:
https://stackoverflow.com/questions/7159348/disable-single-warning-error
This is likely to work well, because it's more work for Developer(s).
They're more likely to take the "easy" option and fix the underlying problem instead of writing all those fiddly "extra" pragma statements. :-)
Don't be tempted to "forget" about warnings globally.