Coaching in person?

Does Executive Coaching work over distance, or does the coaching always need to be "In Person"?

I had an HR person say to me that they want their coaches to be all "In Person", now I guarantee my work, so I'm not sure why? If I can get the same or better outcome then what does it matter? Having said that I do have some views, based on my coaching practice that you might find helpful.
Overall, I prefer 'in person' as I simply find it more fun and you get to see people changing minds in front of you - the whole reason I love what i do. But that necessarily doesn't make it more effective, and cost is a factor. So, what do I suggest?
There is something that happens when people meet in person. There is well documented research on the subject, especially as it relates to communication and trust. Coaching at all levels needs to be a collaboration, the coach and client need to establish a mutual trust and respect. This is best achieved in person wherever possible. The reason being in person helps is that our body and mind communicate at a much higher bandwidth than is possible over a video conference. The subtle, not consciously detectable, ensemble of movements that occurs when people communicate in person is significant and can speed up the process enormously. 
For me, I like and need to know the person I work with. I like to be in the room with them, find something to laugh about, get a sense of the person and their story. However, I don't need to be there every time.
In person can also be inefficient (for everyone). When I meet over video conference, we tend to be more purposeful in our dialogue, more 'on point', there are fewer side-bar conversations and some of the self-indulgence that can occur with a site visit.
My preferred approach is as follows:
Have a reasonably long (2 hours) meeting in person at the beginning of a piece of work, then shift to video conferences for the regular work and occasionally, where possible schedule in person meetings to reconfirm the relationship and collaborative bond that develops. There are just some conversations that are best had in person. So as long as you've got a few opportunities for those, then you ought to be fine.
I've worked with clients in most Capital cities in the country and achieved results regardless of distance. If you are looking for help in this space, don't let distance be a stopper. Yes it is great to meet in person, but there are many advantages to applying technology to get the job done, wherever you are.
If you want to hear more about how to level-up your personal leadership over distance message or call me for more info.