I work at a tech company campus in Palo Alto. I was the company's first EV driver, and at our first startup-warehouse office (before we had the campus) I jury-rigged a charger using two 110v circuits and a combiner (with HR and Facilities' permission). It was a hit, and the 2nd and 3rd EV owners and I traded off as needed.
When we moved into the campus, at my urging, they finally installed a bank of 12 chargers. It took us three years, but now we have about a 2.5:1 EVs:chargers ratio. We recognized early on that this would be a high-demand, limited resource, so we started an internal email list for sharing chargers. It doesn't help that the rest of the campus is about 110% full on parking, so giving up an EV spot means possibly having to park off-campus and walk a good distance, making people not want to give up their chargers unless they truly have to.
Luckily all these issues came up and were talked about company-wide on those EV lists, and we've been able to come up with some decently polite practices; no charger rage so far, though it is still high competition. A hierarchy was established to help solve disputes: charging preference goes to small-battery EVs (Leafs, Fiats, etc) first, then large-battery EV's (teslas), then plug-in hybrids (volts, prii, etc). Within those categories those who have an actual charge need vs. those who just want to top off covers most of the rest. Since the chargers have access cards even though they're free, a user risks losing their access card if they're a jerk about it. It's been decently accountable so far.
My only real complaint is that facilities cheaped out and went with chargers with simple yes/no card controls. I really wish they'd used Chargepoint or something similar where we get visibility into who is using which station when, and we can charge for time, power or per-use access if we need to start limiting use. That would also permit public use (for an appropriate fee) on the weekends and evenings when the chargers are empty, though that's not a big thing. (Like most tech campuses, it's stupidly empty all weekend and not near anything the public would want or need to park at.)
The earlier poster who mentioned a 2:1 sweet spot has it right, and we're past that We're still all polite and finding ways to get around resource contention, but it's more effort than it should be. Facilities knows this and wants to expand, but our overall parking lot has usage issues and losing more spaces to dedicated EV isn't an option right now. That's a bigger problem in general than parking stations that I really hope they solve.
FWIW, 90% of our EVs are of the small-battery-only type (leaf, fiat, focus, soul, etc). Most of our employees commute from somewhere on the peninsula which means they don't have to charge; it's more of a convenience than a need. But there's at least a dozen who commute from the far-south bay area or across the bridges that only squeak by without a midday charge, so it removes charge-anxiety. And for at least three of us, we often have to drive between the two main campus sites and the two datacenters around the bay and having midday charging means we can use an affordable EV (I'm no exec, I can't afford a Tesla!) to great effect. At this point I only have to drive the gas-burner on weekends, which has been a huge cost savings. Plus the use of the carpool lane to get through the gridlock of the south bay freeways is a great benefit... though within the last year or so the carpool lanes are just as crowded as the regular ones, at least during prime time.