Someone recently made a comment to me about the protective case I have for my mobile phone. It's a "Jay & Silent Bob" case. I'm a fan of Kevin Smith's movies and the characters of Jay & Silent Bob in particular.
My friend commented "cool phone case, but you don't bring that to work do you?"
I replied "thanks and of course I do. It's my personal phone, I'll have whatever case I want for it."
Shocked my friend said "But you meet with customers and vendors. Shouldn't you maintain a professional appearance?"
Of course I maintain a professional appearance. I am by no means stiff-as-a-board having tea with the Queen über proper, but I am a professional who has good manners. Part of good business etiquette, is concentrating on the conversions and presentations involved with meeting with customers; not checking my email on my phone or taking a call.
In fact most of the time, when I'm meeting with someone with someone outside of the company, I leave my phone behind. My focus should be on the people who traveled to meet me and the topics they come to discuss.
Of course the phone comes out if my tablet isn't at the ready to check a date on the calendar, or find something I have on Evernote. But it's a brief appearance and my hand usually has awesome graphics covered up.
The point I'm trying to make is: when you meet people face to face, meet them face to face. Not face to face with your eyes on your phone checking email.