Personal bike? Technically probably not, but it's a known personal use nobody frowns about unless the bike is obstructing other traffic (whether foot or vehicle), at which point it'll be taken away. Commercial bike? Same as scooters.

Stroller? If you tried, somebody would probably call a bomb squad. It's not something you do with strollers.

We often left our stroller outside while visiting friends. Never had a bomb squad respond nor anyone seem to give it a second look.