If your blood pressure is already rising, that might mean you've already encountered the request "Can you send me all the raw pictures?". You probably even said yes, but than one weird thing followed another and now you refuse to give out any. "Why Not?"... And the explaining begins... something about not wanting to have those images float around and rights of use, etc. They don't get it. But actually you don't get it either, you are just trying to rationalise that gut feeling. But that's over, I will give you a hint and tell you why I don't give out any raw files:
Raw pictures or .raw files?
I once had a model freak out on me because we agreed prior the shoot that she wants to receive all pictures taken. The problem was not me refusing to give out the pictures I had on my camera, it was me not having all pictures on my camera by the time I finished. While shooting I have manually deleted some pictures right after taking them because they were out of focus, just failed tests or just shots of the empty studio when I was testing the lighting setup - simply said, they were useless. But my - I believe harmless - actions were uncovered by the gaps in the automatic file naming and the model was not pleased. Let's say that if she was right was heavily up to debate, but it's a good example of how people have different definitions of a photographers workflow, product and job.
Let's examine what raw files are first. Or at least what people think they are, because most of them don't mean an actual raw file format, just the unedited full resolution images "straight out the camera". So potentially you can export all the pictures in jpeg to limit the possibilities around altering them - if that makes you feel better and they will be still happy, - although I don't see too much point to this.
Why are you so difficult, you could just give it to them...
You wouldn't use it anyway, they are just going to be deleted or sitting on your hard drive, right? These are the question you might get asked and they are hard to answer. If they also promise you they won't use or alter the pictures than your case is pretty weak at this point, so really, why are you being so difficult?
What is your product?
Did you ever really contemplate what holds the value in your photography services? This is where the answer is and this is what people who don't produce photographs as art are missing:
The raw files are not the products of your work. They are just a tool or a material, like a chunk of clay for a sculptor.
You are not creating pictures, you are creating art, right? The art part is not just pressing the button when your camera points in the general direction of the model. It's also not exporting jpegs. So what is it? Ok-ok, let's not get into that endless debate about the definition of art, but can we agree that it is more of the whole process than those before mentioned things? It is your vision and your final product, the finished image.
Depending on your workflow and the tools you prefer, you might use a digital camera that produces raw files... those files can already be a final product, but most likely you want to vet them and select the ones that are worthy first. You might do some post-processing. You might print them out and paint on them, it doesn't matter, the final product can alter the pictures from the camera so much that they will be unrecognisable.
And that's only one method... if you are a photographer who shoots analogue then there are pretty much no raw files, the closest to them is the scanned negative and I don't think anyone with their right mind would ask for those. A painter doesn't give away a bundle of failed sketches with the final painting, neither should you. Those crappy unfocused, underexposed, awkwardly posed pictures are part of the process and they live in the final product, but are not a product in themselves.
The exception
I have to admit, I would consider giving unedited pictures out in one condition. If the original concept IS to give unedited pictures and they are considered the final product then I am OK with it. But this is a pricey service nonetheless and only those would dare to pay for it who really find value in those images.