Nothing more resembles a group of silverback males like photographers do with their hackles up.
The plain fact is that no matter what you do they can screw it up. You either develop enough of a reputation so that they are afraid to mess with your images, or learn to fight the important battles and not sweat the rest. Personally I have never been asked to deliver raw files, but it would depend on the job and the situation as to whether I made a big issue out of it. I usually choose to educate rather than confront ignorant clients if I want to develop a relationship with the them and this may mean in the short run doing it my way and their way so they can begin to see the difference.
Another way of looking at it
I wish all clients took raws
Then I could get back in front of a camera
My experience is that clients are starting to own 20d etc and taking thier own raw images
So the request is begining to happen
The software and knowledge is spreading
I dont see what is different from a client tinkering with a raw file compared to them tinkering with photoshop
It is so hard to know what a client wants
One example I shot an interior - tungsten -
Standing alone lookin at the images the tungstens look silly - do I correct this ??
Mixed on the contact sheet with the daylight exteriors the tundgsten looks 'warm and inviting' - 'come into my warm hotel out of the cold' - or maybe not - that is subjective
So so much depends on the end use
Better to send raws than be asked for a Tiff of everything wihich takes an age to process out
Its all about communication