I am a Leaf and Volt owner. I am also an eVgo subscriber. I've only had the Volt a few days, and don't do any charging at work or other "long term" spots for either vehicle. But, I do plan to use opportunity L2 charging for either car at restaurants, book stores, or whatever public locations have them. Probably more with the Volt since I want to avoid gas and opportunity charging will help avoid that. With the Leaf, I really only use L3 charging out of need.
What I do always plan to do is put this on my dash... http://www.evchargernews.com/chargeprotocolcard.pdf
For me the most important part of that is leaving a way for people to contact me if they wish to disconnect my car from the charger. We can talk about it, figure out what is best based on each other's specific needs and go from there.
I've already been bad once with my Leaf, leaving it at an eVgo quick charge station while I ate for 45 minutes (the charge finished in 15), but have no problems doing that if I've left a note so they can disconnect without worrying if I'll be mad or call me to come move the car if necessary. All the eVgo stations I've seen (5 of the 6) in Dallas/Ft. Worth are accessible from 2 spots so for my situations, I think the note keep everything cool.
2012 Blue Topaz Metallic Volt delivered 7/31/12 charged with Ecotality Project Blink EVSE
2012 White Diamond Tricoat Volt delivered 6/29/12 charge with Ecotality Project Blink EVSE
2012 Cayenne Red Leaf delivered 3/29/12 charge with eVgo/Aerovironment EVSE
6kW Solar array