1. Don't ride on the sidewalk, but I bet you know that already.
2. It's doubtful NYC police really know what an e-bike is well enough to know one by seeing it.

E-bikes have no legal status here in pennsylvania, meaning that on an e-bike you're just riding an un-registered moped. But the police aren't interested in lowly e-bike riders any more than they're interested in red-light-running cyclists, folks who use bike lanes as 15 minute parking spaces, or people who do "rolling stops".