Generally, a "scooter" is any two-wheeled machine with 50cc or less motor with 5hp or less output. It really has nothing to do with the design, i.e. a pasola vs. motorcycle. A pasola can be a serious motorcycle like the Honda Silver Wing or Suzuki Burgman (with a top speed of 220kmh:surprised.)
Depending on the country/jurisdiction many do not need to be registered or licensed, but often there are restrictions as to where they can be used. For an example, in the states expressway onramps often have a sign prohibiting vehicles under 5hp from access.
Often no drivers license is required to operate a scooter, but required for a motorcycle. Note in the DR that many young kids (under 16) ride scooters while older folks ride motorcycles.
There is a reason many small motorcycles have a 50cc motor, and not 55 or 60.
I'm not sure what the law in the DR is,but it's rare to see AMET load a Jog or similar 50cc bike onto a flatbed during a paper check. The 100-125cc bikes? All the time...