Unfortunately, although it's more likely that someone who's had an EV for awhile has learned proper charging etiquette, it's still very possible they might not know, esp. if they rarely use public charging, don't communicate w/other EV/PHEV drivers and don't participate in online forums (e.g. this one, MNL, Facebook groups for their car, etc.) and/or aren't enthusiasts.
I carry copies of both of these charging protocol cards in my Leaf:
http://www.evchargernews.com/chargingprotocol.htm
http://www.pluginamerica.org/evcard
I use the 1st one if the location w/7 J1772s is close to full.
At the CHAdeMO DC FCs I use, if I leave my car, I put up an 8.5 x 11" sign that has my phone # that says something to the effect of, call me you urgently need to charge or if you see that my car has fallen to 7.0 kW power level or 17 amps (for the ones that read only volts and amps instead of kW, as DC FCing for me is ~400 volts and 17 amps = 6.8 kW). At that point, I'm down to L2 speed.
Although this doesn't directly relate to charging etiquette, here are some interesting/surprising "street encounter" stories w/other Leafers:
- http://www.mynissanleaf.com/viewtopic.php?p=349448#p349448 - guy who had his Leaf for at least 2 years didn't know anything about the Leaf's capacity bars, didn't realize he'd lost some and it sounded like he didn't understand the snail mail he should've gotten about the capacity warranty that was retroactively added to his Leaf: http://www.mynissanleaf.com/viewtopic.php?f=4&t=13192
- http://www.mynissanleaf.com/viewtopic.php?p=362230#p362230 - I've encountered the guy w/the '14 S I mention there a few times, including last night (8/10/14). So, he's had his '14 Leaf (which has the charging lock switch that his '11 didn't have) 4+ months and we last night talked about the lock switch. He didn't know the behavior of the 3 lock switch's positions: AUTO, middle/nothing (always unlock) and LOCK. I brought that up because of this incident at http://www.mynissanleaf.com/viewtopic.php?f=27&t=15827 at the same location.
- someone else's street encounter: http://www.mynissanleaf.com/viewtopic.php?p=268304#p268304
- Over the weekend, near the end of https://www.fremont.gov/2089/Experience-Electric-Campaign that I attended. A volunteer was there answering questions about his own Leaf/EVs. We talked a bunch and then apparently, he's had his '13 Leaf S for ~1.5 years (1/2 year longer than I've had mine) yet he wasn't on mynissanleaf.com nor was he on https://www.facebook.com/groups/BayLeafs/. It sounded like he'd heard of neither, which is surprising.
And, there are others who just don't get in terms if charging etiquette and probably never will.
Examples below.
http://www.mynissanleaf.com/viewtopic.php?p=357102#p357102 is a guy apparently frustrated by a particular Volt lingering all day at an L2 spot when that guy could move his car or his a 120 volt outlet instead.
http://www.mynissanleaf.com/viewtopic.php?p=240056#p240056, http://www.mynissanleaf.com/viewtopic.php?p=242899#p242899 and http://www.mynissanleaf.com/viewtopic.php?p=271535#p271535 mainly point to a Volt driver that was ruining things at Mitsubishi's station in So Cal for everyone else. I think they finally put an end to that.