It's true that if you are only used to shooting digital - where it is so easy to blowout highlights, that you might expose the scene as a digital camera would. Well, you will find most film to be near impossible to blowout. Below you will notice that while digital raws are completely unusable by about +3 or +4 stops, film just seems to keep going.
So unless you are good with metering and your camera is performing as it should, you should always err on the side of overexposure as it will be far easier to deal with then grossly underexposing. I have personally tested many color and b&w films and they can all handle quite a bit of overexposure.