Ok, I'll bite this one:
If on the sidewalk I park half a dozen plus one bicycles (which now take up more space than one motorcycle/scooter, or whatever equivalent), I don't get a ticket.
You have, however, accommodated 7 commuters rather than just one or two, and they've likely used the provided posts to secure their vehicles, which keeps them in a single area.
If on the sidewalk I park one large bicycle that takes up more space than one motorcycle/scooter, or whatever equivalent), I don't get a ticket.
Because it's a bicycle, not a motor vehicle, for which parking on the street carries extra hazards. It also isn't likely to leak oil or gas, and there are damned few that are that big. I believe that they're generally referred to as rickshaws or peddle cabs.
If on the sidewalk I park a motorcycle (or scooter, or whatever equivalent) that doesn't have an engine, it's technically not a motor vehicle, and I don't get a ticket.
No, but it's likely classed as an abandoned vehicle and towed on spec. Whether it has a motor or not, it's still a 'motor vehicle.' Playing semantics doesn't work.
If on the sidewalk I park a motorcycle (or scooter, or whatever equivalent) that DOES have a engine, by pushing it there under my own manpower, since its engine was off the whole time, I do get a ticket.
It's a motor vehicle and belongs on the street or in a parking lot. Haven't we already been through that?
I await an excellent counterargument from physics that shows why this makes sense.