I agree with you 100%. Even at the traditional level with the +/- tolerances on color matching, there will still be issues. That is why you need to clearly indicate to the client that colors on screen are an approximation and may not be representative of what they will see on paper or another substrate.
I've been working with Pantone color guides (previously referred to as PMS Guides) since 1990. Exact color matching is a science in itself and I've done thousands of "draw-downs" for clients. I assist my clients with their color requirements day in and day out. It can be a frustrating experience sometimes trying to explain why the plant did not match the color exactly. It could have been raining that day, too much moisture in the air, pressman was a little hungover from a party the previous night, paper stock sucked up more ink than we expected, etc. I enjoy it immensely!