Dealership charge stations in my experience are not all created equally.
I think there can be some generalizing by company though.
Nissan dealers seem to only expect Leafs to charge there. But they do expect people to use their units not just when shopping at the dealership. They made a big push for DCQCs at all dealerships, and I believe free access to those to extend range is a marketed feature of the Leaf, at least the trim with QC. The level 2 units are usually positioned next to the DCQC, in an easily accessed location front and center of the dealership. I can't imagine they would get mad if you pulled into an open spot and plugged in, but I'm not sure they'd move their Leafs out of a spot for you. As an aside, our local Nissan dealer sponsored a free level 2 unit at a nearby college, so that was cool.
Ford dealers usually don't expect anyone to use their Chargers. They mostly view charging as a courtesy to customers, as Wattsup says. But I'm not sure how much courtesy they really offer-- every Ford dealership I've seen has the outside charger out of view toward the back where the employees park. I've made three service stops at two dealerships since buying the car, and every time the level 2 was powered down and someone had to figure out where the switch was to turn it on so I could charge before leaving. They were always nice about it, though. I just think it isn't requested often. When I purchased my FFE I was told that all EV certified dealers also have chargers in the servicing area, yet oddly in 3 service visits they never plugged me in while performing whatever work was indicated. At least one guy here posted an issue where he was sort of promised access to the dealer's charger whenever if he bought from them, and later made to feel unwelcome charging there.
BMW expects people to use their chargers. The few I've noticed around here have Chargepoint units. At least one is free to Bimmers and the usual chargepoint cost to anyone else.
But anyway dealerships are rarely in a location one would want to spend 2-3 hours, so I agree they would be of limited utility even if the dealers were more cooperative. And all but the BMWs around here are turned off and/or located in gated lots after hours and on weekends, when I would most likely find myself in need of an emergency charge. For what it's worth, I would love for Tesla to throw the rest of us a bone and plop down a few Level 2s wherever they have Superchargers. The fractional additional cost would be tiny, many are in prime locations where they could even charge a premium fee for these, and the stark contrast of Level 2 charging with supercharging would provide quite the advertising to a target audience.