As a consultant and employee, I would be a bit surprised by such an email because I'm not in a position to hire people. But my manager is always looking for people and we have a referral bonus system, so I would get some money for introducing someone to my manager who gets hired. Both me and my manager would have selfish reasons for seeing you, apart from just being nice people that want to help others out.
If you suggest a coffee close to their office, I don't see a problem. They'll either ignore your email, tell you they're busy, or meet up. I would definitely suggest that you make your intentions clear that you're looking for a job, but also that you're interested in learning more about the job or the industry. I would also suggest that you say how you found the person, otherwise they may be more suspicious or confused. Just say if you found them on LinkedIn, on the company website, or wherever, so that they know where you're coming from.
Good luck!