Vespa is about 3-5 times the weight of an e scooter and I assume yours runs in gasoline, so not really a fair comparison but if going under 20mph on the sidewalk is what you consider the safest course of action in a specific circumstance then I’m not sure anybody would fault you for it. Or just get yourself an e-scooter if you use your Vespa for very short trips. The convenience of being able to ride in safer locations where you’re not having to be hyper vigilant of not only your own actions but also those of cars that might very quickly end your life because someone was texting is pretty nice.

I ride a motorcycle too (not even on the sidewalk) and can tell you for a fact that e scooters are night and day safer transportation under normal use cases.