> Some people are so non-technical, that they will not understand what you are explaining to them, or why you are even bothering them. You will be perceived as a tinfoil hat wearing conspiracy theorist. Some people will understand what you are explaining and might even understand your stance, but ultimately will still continue in their ways because it's so much easier and convenient.
This is a very common reaction I've seen. People don't care as much about privacy as one would assume they might when given some information about it. It's like a case of extreme apathy triggered and nurtured by ignorance. Add to this the convenience factor of Gmail or similar platforms, it's a big task.
But I have seen that there are at least a few people who, over time, get the heeby-jeebies about privacy intrusions. That's a good result compared to not telling them about this over and over for a long time.