As a non EV or PHEV owner, this issue doesn't impact me but it's something I didn't ever wonder about until a) this thread and b) literally seeing today, a real life example of experiences shared in this thread.
I walk to work everyday, walking through our local train station car park on my journey and this car park has just had public charging points installed, although I don't think they're active yet based on the notices on the charging points themselves.
Today, an Outlander PHEV was parked in one but wasn't connected (assuming because they're not active yet). The other 8 odd charging bays were empty, as if others knew parking there wasn't a good idea considering the parking wardens will take a mile if you give an inch. So if either an BEV or PHEV is parked in a space but isn't plugged in, would they get a ticket?