Any halfway decent software shop will have a policy of compiling with all warnings enabled
FWIW, your definition of "halfway decent" would exclude most software shops in the world.
It is extremely unprofessional to disable or ignore warnings such as the "unused function parameter" warning
Unused function parameter warnings are often noise (e.g., due to #ifdefs, unimplemented APIs, backward compatible APIs, etc). I agree that code should compile w/o warnings, but the benefits of tracking down and squelching unused function argument warnings are pretty marginal in my experience.